“I’m wondering how words contain any meaning at all, but then also how definition is then anyway attached to meaning. Why should the definition have a meaning? Does meaning have definition?”
Saussure is undoubtedly one of the most important thinkers of the twentieth century. Almost single-handed he created the modern field of linguistics.
Saussure saw that language is a system of difference. This radical idea holds that the sign is a combination of a form or signifier and a concept or signified. These two parts of the sign is arbitrary (there is no natural link between them). This is why the animal dog is called by various names (signifiers) in different languages. We start with a concept then we give it a name. A word in a language only gains meaning from all other words it is held up or contrasted against, not to have full meaning in itself. This is what Derrida had meant by saying words never have full presence of meaning since it relies on all other words for its meaning. Wittgenstein thought the same way when he said the meaning of a word is its use in the language.
Saussure also gave us the concept of langue and parole. Langue is the language as a system (like the dictionary of words, books of grammar) not in use but in theory. Parole is the actual real world use of the language.
Another way to look at language as syntagmatic across a chain of words in a sentence, or as paradigmatic by cycling through possible words in a position. The position ‘in’ for example in the previous sentence can be theoretically replaced by ‘on’, ‘at’, ‘to’, etc, under the correct circumstances and desired meaning may actually be viable.
Yet another way to look at language is synchronically as snapshot in time (late twentieth century) or diachronically as a series of snapshots (language change, etymology, language death, linguistic imperialism, etc).
Cognitive linguistics gave us conceptual metaphor theory which explained why words may have more than one meaning. A person may in physical space of a kitchen. But he may also be in a social club not exactly a space but an organisation. He may also be in love even though love is not a space. This kind of extension stems from not only the limit of talking of literal situations (basic schema) but also because we have a need to talk about some things which can only be explained from extensions. But in some ways going against Saussure in that these extensions are not arbitrary but also systematic in some way explains why language changes and grows so to speak. In other words, abstract concepts must rely on literal ones in order to be conceptualised and verbalised.
Language is never fixed. It changes not only slowly but continually. Every use of language necessarily changes it (iterability). We may have a fixed idea about language like a dictionary or grammar book (prescriptive) but really it is from the real world that language receives all its meaning (descriptive), where, for example, intentional meaning and relevance comes into play.