A lexical set is a set of words that all relate to the same topic or situation, for example, words for furniture, words for describing graphs, words for describing different kinds of movement. Vocabulary teaching at beginner or elementary levels is often based around lexical sets.
"Here are some possible words from the lexical set for reading: books, blogs, text, to read, to skim, to scan, page, print, ink, printing, font size, glasses."
Here are some for the lexical set for cooking: boil, stir, stew, burn, mix, saucepan, bowl, recipe, spoon, oven.
Nation, P. (2011). Learning Vocabulary in Lexical Sets: Dangers and Guidelines. TESOL Journal 9/2.
Thornbury, S. (2006) An A-Z of ELT. Oxford: Macmillan.
Wells, J.C. (1982). Accents of English. Cambridge: Cambridge University Press.