I. o ‧ ver ‧ lay 1 /ˌəʊvəˈleɪ $ ˌoʊvər-/ BrE AmE verb ( past tense and past participle overlaid ) [transitive]
1 . to cover or be on top of something
be overlaid with something
The wood is overlaid with silver.
2 . if one quality, sound etc overlays another, it is added to it and is often stronger or more noticeable:
The roar of the engines was overlaid by a loud banging.
II. o ‧ ver ‧ lay 2 /ˈəʊvəleɪ $ ˈoʊvər-/ BrE AmE noun [countable]
1 . something which covers something else:
the brass fire surround with its decorative overlay
2 . a transparent sheet with a picture or drawing on it which is put on top of another picture to change it
3 . an additional quality or feeling:
sad stories with an overlay of humour