initials
n. countable B1 Intermediate US //ˌɪˈnɪʃəɫz// UK //ɪnˈɪʃəlz// ini·tials
n. the first letters of your names. For example, if your name is John Smith, your initials are J.S.
n. the first letter of each word in a person's full name or a multi-word title. Often used as a shorthand signature or for marking personal property.
He carved his initials into the wooden desk.
Please write your full name on the first page and your initials on every other page of the contract.
The artist chose to sign the corner of the canvas with his initials rather than his full surname to maintain the painting's minimalist aesthetic.
Usage
Usually used in the plural form when referring to a person's full set of first and last name letters.