n.
Pronunciation: ' ō -v ə (r)- ˌ chu ̇ r, -ch ə r, - ˌ tyu ̇ r, - ˌ tu ̇ r
Function: noun
Etymology: Middle English, literally, opening, from Anglo-French, from Vulgar Latin *opertura, alteration of Latin apertura ― more at APERTURE
Date: 15th century
1 a : an initiative toward agreement or action : PROPOSAL b : something introductory : PRELUDE
2 a : the orchestral introduction to a musical dramatic work b : an orchestral concert piece written especially as a single movement in sonata form