pinch out

Short definition from Wiktionary

Verb

1. 1
   To remove the shoots of a plant: the leading shoot in order to encourage a bushy habit
2. 2
   To remove the shoots of a plant: a plant's side shoots
3. 3
   For a distinct body of rock between underlying and overlying strata, to thin out and come to an end, so that the strata above come to lie on the strata below.

Noun

1. 1
   A volume of rock or oil trapped or isolated between strata that have pinched it out.
2. 2
   Alternative form of pinch out.