3.326 In order to recognize the symbol in the sign one must look to the meaningful [sinnvollen] use.

To know the (meaningful, significant, or ‘sensical’) use is, it seems, to know the symbol. In Letters to Ogden, p. 59, Wittgenstein writes: “The meaning of this prop[osition] is: that in order to recognize the symbol in a sign we must look at how this sign is used significantly in propositions. I.e. we must observe how the sign is used in accordance with the laws of logical syntax. Thus “significant” here means as much as “syntactically correct”.” I have ‘meaningful’ instead of ‘significant’.