1. [n]  a project of personal concern to someone; "this project is his baby"
2. [n]  a very young mammal; "baby rabbits"
3. [n]  (slang) sometimes used as a term of address for attractive young women
4. [n]  the youngest member of a group (not necessarily young); "the baby of the family"; "the baby of the Supreme Court"
5. [n]  a very young child (birth to 1 year) who has not yet begun to walk or talk; "isn't she too young to have a baby?"
6. [n]  an immature childish person; "he remained a child in practical matters as long as he lived"; "stop being a baby!"
7. [adj]  (of crops) harvested at an early stage of development; before complete maturity; "baby carrots"; "new potatoes"; "young corn"
8. [v]  treat with excessive indulgence; "grandparents often pamper the children"; "Let's not mollycoddle our students!"

BABY is a 4 letter word that starts with B.

1. \Ba"by\ (b[=a]"b[y^]), n.; pl. {Babies} (-b[i^]z). [Dim. of
   babe]
   An infant or young child of either sex; a babe.
   2. A small image of an infant; a doll.
   {Babies in the eyes}, the minute reflection which one sees of
      one's self in the eyes of another.
            She clung about his neck, gave him ten kisses, Toyed
            with his locks, looked babies in his eyes.
                                                  --Heywood.
   

2. \Ba"by\, a.
   Pertaining to, or resembling, an infant; young or little; as,
   baby swans. ``Baby figure'' --Shak.
   

3. \Ba"by\, v. i. [imp. & p. p. {Babied} (?); p. pr. & vb.
   n.{Babying}.]
   To treat like a young child; to keep dependent; to humor; to
   fondle. --Young.