some definitions of the sign from Peirce
I thought it might be interesting/helpful to take a look at some of the later (1906-1909) explanations Peirce gives of his use of the word "sign", partly because essius has mentioned that "determines" can seem rather vague. Both of these, of course, don't essentially differ from Peirce's 1903 description of the sign as a triadic relation, and as such having a first, second, and third correlate and not just three dyadic relations between sign, object, and interpretant. However, in some ways, these definitions seem particularly clear, perhaps because he gives them in letters to friends, perhaps because his own concepts are clearer at this point.
I use the word "Sign" in the widest sense for any medium for the communication or extension of a Form (or feature). Being medium, it is determined by something, called its Object, and determines something, called its Interpretant or Interpretand. But some distinctions have to be borne in mind in order rightly to understand what is meant by the Object and by the Interpretant. In order that a Form may be extended or communicated, it is necessary that it should have been really embodied in a Subject independently of the communication; and it is necessary that there should be another Subject in which the same Form is embodied only in consequence of the communication. The Form (and the Form is the Object of the Sign), as it really determines the former Subject, is quite independent of the sign; yet we may and indeed must say that the object of a sign can be nothing but what the sign represents it to be. Therefore, in order to reconcile these apparently conflicting truths, it is indispensible to distinguish the immediate object from the dynamical object.
-Peirce, "Excerpts from Letters to Lady Welby", EP2 p.478
A Sign is a Cognizable that, on the one hand, is so determined (i.e. specialized, bestimmt) by something other than itself, called its Object (or, in some cases, as if the Sign be the sentence "Cain killed Abel," in which Cain and Abel are equally Partial Objects, it may be more convenient to say that that which determines the Sign is the Complexus, or Totality, of Partial Objects. And in every case the Object is accurately the Universe of which the Special Object is member, or part), while, on the one hand, it so determines some actual or potential Mind, the determination whereof I term the Interpretant created by the Sign, that that Interpreting Mind is therein determined mediately by the Object.
This involves regarding the matter in an unfamiliar way. It may be asked, for example, how a lying or erroneous Sign is determined by its Object, or how if, as not infrequently happens, the Object is brought into existence by the Sign. To be puzzled by this is an indication of the word "determine" being taken in too narrow a sense. A person who says Napoleon was a lethargic creature has evidently his mind determined by Napoleon. For otherwise he could not attend to him at all. But here is a paradoxical circumstance. The person who interprets the sentence (or any other Sign whatsoever) must be determined by the Object of it through collateral observation quite independently of the action of the Sign. Otherwise he will not be determined to [the] thought of that object. If he never heard of Napoleon before, the sentence will mean no more to him than that some person or thing to which the name "Napoleon" has been attached was a lethargic creature. For Napoleon cannot determine his mind unless the word in the sentence calls his attention to the right man and that can only be if, independently, [a] habit has been established in him by which that word calls up a variety of attributes of Napoleon the man. Much the same thing is true in regard to any sign.
-Peirce, "Excerpts from Letters to William James", EP2 492-493
Edit: If anybody wants to, you know, question or argue this in any way, I am totally up for it. I will defend the Interpretant! and the Immediate and Dynamical Object distinction! C'mon, who wants to believe somebody like Saussure who thought thought was all nebulous and vague before linguistic structure?
I use the word "Sign" in the widest sense for any medium for the communication or extension of a Form (or feature). Being medium, it is determined by something, called its Object, and determines something, called its Interpretant or Interpretand. But some distinctions have to be borne in mind in order rightly to understand what is meant by the Object and by the Interpretant. In order that a Form may be extended or communicated, it is necessary that it should have been really embodied in a Subject independently of the communication; and it is necessary that there should be another Subject in which the same Form is embodied only in consequence of the communication. The Form (and the Form is the Object of the Sign), as it really determines the former Subject, is quite independent of the sign; yet we may and indeed must say that the object of a sign can be nothing but what the sign represents it to be. Therefore, in order to reconcile these apparently conflicting truths, it is indispensible to distinguish the immediate object from the dynamical object.
-Peirce, "Excerpts from Letters to Lady Welby", EP2 p.478
A Sign is a Cognizable that, on the one hand, is so determined (i.e. specialized, bestimmt) by something other than itself, called its Object (or, in some cases, as if the Sign be the sentence "Cain killed Abel," in which Cain and Abel are equally Partial Objects, it may be more convenient to say that that which determines the Sign is the Complexus, or Totality, of Partial Objects. And in every case the Object is accurately the Universe of which the Special Object is member, or part), while, on the one hand, it so determines some actual or potential Mind, the determination whereof I term the Interpretant created by the Sign, that that Interpreting Mind is therein determined mediately by the Object.
This involves regarding the matter in an unfamiliar way. It may be asked, for example, how a lying or erroneous Sign is determined by its Object, or how if, as not infrequently happens, the Object is brought into existence by the Sign. To be puzzled by this is an indication of the word "determine" being taken in too narrow a sense. A person who says Napoleon was a lethargic creature has evidently his mind determined by Napoleon. For otherwise he could not attend to him at all. But here is a paradoxical circumstance. The person who interprets the sentence (or any other Sign whatsoever) must be determined by the Object of it through collateral observation quite independently of the action of the Sign. Otherwise he will not be determined to [the] thought of that object. If he never heard of Napoleon before, the sentence will mean no more to him than that some person or thing to which the name "Napoleon" has been attached was a lethargic creature. For Napoleon cannot determine his mind unless the word in the sentence calls his attention to the right man and that can only be if, independently, [a] habit has been established in him by which that word calls up a variety of attributes of Napoleon the man. Much the same thing is true in regard to any sign.
-Peirce, "Excerpts from Letters to William James", EP2 492-493
Edit: If anybody wants to, you know, question or argue this in any way, I am totally up for it. I will defend the Interpretant! and the Immediate and Dynamical Object distinction! C'mon, who wants to believe somebody like Saussure who thought thought was all nebulous and vague before linguistic structure?