Final answer:
Adam is most likely to learn about the meaning of words and phrases in his lecture on semantics.
Step-by-step explanation:
In his lecture on semantics, Adam is most likely to learn about the meaning of words and phrases. Semantics is the branch of linguistics that deals with the meaning of words and how they convey meaning in sentences. It is concerned with understanding how language users interpret words and phrases in different contexts. By studying semantics, Adam will gain insight into how meanings are assigned to words and how they contribute to overall communication.