'bottom-up' definitions:

Definition of 'bottom-up'

(from WordNet)
adjective
Of an approach to a problem that begins with details and works up to the highest conceptual level; "bottom-up parser"; "a bottom-up model of the reading process" [ant: top-down]

Definition of 'bottom-up'

From: GCIDE
  • bottom-up \bottom-up\ adj. (Computers) planning or building the smallest parts first; as, bottom-up programming. Opposite of top-down. [WordNet 1.5] Bottony