(suffix) a courtesy title, used after one's name or surname, to address children, people younger than you (especially girls), or loved ones.
Used for young children, pets, boyfriends or girlfriends. Diminuative
A suffix meaning cute or darling one, a term of affection usually reserved for for romantic partners, young female friends, small animals or children. A good example of this word would be P-Chan (Ryoga) from the Ranma 1/2 series.