ABSTRACT. Various criss-crossing distinctions have been drawn in the philosophical tradition between kinds or dimensions of linguistic meaning or between meaning and other dimensions of linguistic function. In this chapter I'll try to collect together from various books and papers the results of my own investigations on different aspects of meaning. The underlying idea is that to understand how language works, one must look, first, to the cooperative functions that various language forms perform, understanding these on a biological model as what these forms accomplish that keeps them in circulation. To explain the cooperative function of a language form is to explain its survival value, the source of its proliferation, what it does that accounts at the same time for the fact that speakers continue to use it and that hearers continue to react to it often enough in standard ways. Next we should look at language mechanics, at how language forms perform their functions. For some language forms there are conditions in the world that are necessary to support their functions and that vary systematically with certain variations in the forms themselves. These are truth conditions, and they are determined by a kind of "meaning" that I will call "semantic mapping functions" - "functions", this time, in the mathematical sense. (Semantic mapping functions determine truth conditions; truth conditions only delimit and do not determine semantic mapping functions. I will get to this.) Last we need to describe the psychological mechanisms that are involved in implementing the functions of various language forms, the ways that speakers and hearers manage to produce and understand these forms so as to promote performance of their cooperative linguistic functions.