We can define the semantics of a compound logical expression using a truth table that specifies the value of the compound for each possble combination of its parts. If a compound has n distinct components, then it will have 2n rows in its truth table.
Here is a truth table for the basic connectives of propositional logic:
p | q | not p | not q | p or q | p and q | p implies q |
T | T | F | F | T | T | T |
T | F | F | T | T | F | F |
F | T | T | F | T | F | T |
F | F | T | T | F | F | T |