Definition of outpocketing in US English:

outpocketing

noun

Biology
  • An outward growth or movement of part of a surface so as to form a pocket-like or sac-like cavity; the cavity so formed.

Origin

Early 20th century; earliest use found in Science. From out- + pocketing.

Pronunciation

outpocketing

/ˈaʊtpɒkɪtɪŋ/