What is the meaning of 'm?

Am, used especially in I'm.

Various forms of be.

Alternative form of 'em

Represents the word madam or ma'am when used as a formal address of a female; as in yes'm and no'm.

a

the

Contraction of me.

my

me

Contraction of hem.

Reduced form of jam (you, you all, subject)

my

me

Contraction of ddim (not).

Source: wiktionary.org