MEANING ... Let's take a moment to make sense of meaning (or at least see how other people do.) What kinds of things mean something? Words? We usually think those mean something. Signs? Sure, I'll give you that. Body language? Okay. Buildings? I don't know. Rocks? Again, I don't know about that.
Let's just focus on words, signs & body languages - the ones we're comfortable saying mean something. What do they have in common, as far as their meaning goes? They all have some on-the-surface symbolic feature - something that they are, like a painted sign with a specific pattern, a sequence of letters, an arm with fingers held in a certain way. But we also take them all to stand for something else. Meaning is what makes this possible.
To use the traditional term, we could call all of these signs. Then we'd say that all of these signs stand for something. We'd call this relationship meaning.
In linguistics, semantics hashes out this relationship between words and phrases and their meanings. Some quirks come up when you look at meaning in language. One major one is fuziness. Words don't necessarily have fixed, independent meanings. Think of words like pizza, cheese, sauce, bread. We don't take these to mean the same thing, but they all depend on each other in a way, and each one encompasses a different range of things for different people in different cuisines.
Form and meaning don't match or parallel each other. The relationship between them is mostly arbitrary. There's nothing about the sound or shape of the English word 'cheese' or for that matter the Italian word 'formaggio' that inevitably link them to this meaning.
Meaning changes over time. The Old English word 'sælig' meant 'fortunate', but that word, now pronounced 'silly', means something quite different. If you're interested in meaning and the etymology of words, here's a video with more on meaning change.
Also, context really matters for meaning in language, and ambiguity lingers around many corners. If I tell you, "he turned red", you can imagine a few possibilities. This kind of issue brings the actions surrounding any bit of language to our attention. Linguists have a term for this context that feeds the meaning of any piece of language: pragmatics. That's the fancy term for the context sensitivity of meaning.
Context isn't just important for recognizing the meaning of words. The faces people make, the tone somebody uses, touch or body movement, all communicate something about meaning. Subtler factors even come into play, like how far or close somebody is standing, which in the 1960's one anthtropologist termed proxemics.
Escaping beyond immediate interactions with other humans, we also think that physical signs and symbols have meaning. I already admitted as much about this particular sign earlier. Gathering up all the different meaningful signs and studying how they work is the business of semiotics. Semantics in language, semiotics in signs in general, but enough of this name-dropping.
Meaning matters in logic, too. But here it's not so much about how context and communication impact meaning, but about the role meaning plays in reasoning, arguing and thinking. I can take thoughts like "she likes tofu & he likes ice cream", "she likes ice cream & he likes tofu", "she likes ice cream & he likes ice cream" and reduce them to a common pattern: x & y. That pattern is the logical form we see in all three sentences. Now, the three of them don't mean the same thing - once we assign meanings to that bit of logic, we get three sentences, and we can tell if they're right or not. Of course, we need to define some of the words. Who is he? Who is she? What exactly counts as tofu? How would we know that they like it? Here the focus is on defining words, clarifying meaning and avoiding pitfalls like using vague language to arrive at a false conclusion.
As long as I'm asking questions, here are some more general ones :