concentrate-v; 3 Senses

Sense Number 1: focus on, center upon

Examples:
Her entire attention was concentrated on her children.
Please concentrate on your studies and not your hobbies.
So I concentrated on the rhythmic side of things, and therefore left a lot of holes.
You've got to concentrate bigtime.
His reflexes were slowing as he tried to concentrate on the game.

Mappings:
VerbNet: focus-87.1
FrameNet: NP
PropBank: concentrate.01
WordNet 3.0 Sense Numbers: 2
WordNet Verb Particle Constructions, Multiword Expressions:
concentrate_on 1

Sense Number 2: cluster or gather together, as by condensing all elements

Examples:
Because their electrons aren't as tightly concentrated, the resulting attraction is too weak.
In the district of Krosno the occupiers concentrated the Jew population in the ghettos.

Mappings:
VerbNet: NM
FrameNet: NP
PropBank: NM
WordNet 3.0 Sense Numbers: 3, 5, 6

Sense Number 3: make purer, more intense, as by removal of extraneous elements

Examples:
The cook concentrated the sauce by boiling if for a long time.
A series of five emptied bladders concentrated the bile coming to them.
I concentrated the sample to dryness, then dissolved in ethyl acetate.

Mappings:
VerbNet: NM
FrameNet: NP
PropBank: concentrate.02
WordNet 3.0 Sense Numbers: 1, 4, 7, 8