To form the three degrees of comparison of (an adjective).
To be similar (often used in the negative).
To assess the similarities and differences between two or more things ["to compare X with Y"]. Having made the comparison of X with Y, one might have found it similar to Y or different from Y.
To declare two things to be similar in some respect ["to compare X to Y"].
An instruction or command that compares two values or states.
Comparison.