1 giving all your attention/effort to sth
ADJ. deep, great, intense | total a look of total concentration on her face | poor | exclusive
VERB + CONCENTRATION demand, require The game requires great concentration. | lose | break, disturb Don's voice from outside broke my concentration.
CONCENTRATION + NOUN span
PREP. ~ on his concentration on his writing
PHRASES a lack of concentration, a lapse in/of concentration One momentary lapse in concentration could prove fatal. | powers of concentration She has great powers of concentration for a child her age.
2 large number/amount of sth in one place
ADJ. great, heavy, high, large The greatest concentration of traffic is in the city centre. | low | geographical
CONCENTRATION + VERB increase, rise The concentration of nitrates in the drinking water has risen in recent years. | decrease, fall