noun
1.
[ sing. , U ] an increase in the amount of sth over a period of time :
a steady build-up of traffic in the evenings
2.
[ C , usually sing. ] build-up (to sth) the time before an important event, when people are preparing for it :
the build-up to the President's visit
3.
[ C , usually sing. ] a very positive and enthusiastic description of sth that is going to happen, that is intended to make people excited about it :
The media has given the show a huge build-up.