commemorate
The definition for commemorate is "To mark by a ceremony." Used in a sentence: Each year, the Franklins commemorate their anniversary by visiting the site of their first date.
finite
The definition for finite is "Having definite limits." Used in a sentence: The exasperated mother had finite patience for her toddler's tantrums.
incumbent
The definition for incumbent is "Necessary as a duty or responsibility." Used in a sentence: It was incumbent on Jack to attend his father's retirement party.
parity
The definition for parity is "Equality." Used in a sentence: Hilda, to avoid squabbles, aimed for parity in the slices of birthday cake.
ramble
The definition for ramble is "To wander, physically or in language." Used in a sentence: Professor Tan rambled during his lectures, frequently straying from the subject.