From Wiktionary, the free dictionary
From spouwen (“to split”).
spouw m (plural spouwen, diminutive spouwmuurtje n)
- an air gap, a cavity (e.g. in a cavity wall)
See the etymology of the corresponding lemma form.
spouw
- inflection of spouwen:
- first-person singular present indicative
- (in case of inversion) second-person singular present indicative
- imperative