What is the study of words and their meanings called?

What is the term for words that have similar meanings?

What is the term for words that have opposite meanings?

What is the term for words that sound the same but have different meanings and spellings?

What is the term for words that are spelled the same but have different meanings and pronunciations?

What is the term for the smallest unit of meaning in a language?

What is the term for the study of the way words are arranged in a sentence?

What is the term for the meaning of words and phrases in a language?

What is the term for the study of language in use, including the social and cultural factors that influence it?

What is the term for words that are unique to a particular language or culture?