The Collaborative International Dictionary of English v.0.48:
Scrub \Scrub\ (skr[u^]b), n.
1. One who labors hard and lives meanly; a mean fellow. "A
sorry scrub." --Bunyan.
We should go there in as proper a manner as
possible; nor altogether like the scrubs about us.
2. Something small and mean.
3. A worn-out brush. --Ainsworth.
4. A thicket or jungle, often specified by the name of the
prevailing plant; as, oak scrub, palmetto scrub, etc.
5. (Stock Breeding) One of the common live stock of a region
of no particular breed or not of pure breed, esp. when
inferior in size, etc. [U.S.]
6. Vegetation of inferior quality, though sometimes thick and
impenetrable, growing in poor soil or in sand; also,
brush; -- called also scrub brush. See Brush, above.
[Australia & South Africa]
[Webster 1913 Suppl. +PJC]
7. (Forestry) A low, straggling tree of inferior quality.
[Webster 1913 Suppl.]
Scrub bird (Zool.), an Australian passerine bird of the
family Atrichornithidae, as Atrichia clamosa; --
called also brush bird.
Scrub oak (Bot.), the popular name of several dwarfish
species of oak. The scrub oak of New England and the
Middle States is Quercus ilicifolia, a scraggy shrub;
that of the Southern States is a small tree (Quercus
Catesbaei); that of the Rocky Mountain region is Quercus
undulata, var. Gambelii.
Scrub robin (Zool.), an Australian singing bird of the