verb , noun
■ verb / ˌəʊvəˈleɪ; NAmE ˌoʊvərˈleɪ/ ( over·laid , over·laid / -ˈleɪd; NAmE /) [ vn ] [ usually passive ] overlay sth (with sth)
1.
( technical ) to put sth on top of a surface so as to cover it completely; to lie on top of a surface :
wood overlaid with gold
2.
( literary ) to add sth, especially a feeling or quality, to sth else so that it seems to cover it :
The place was overlaid with memories of his childhood.
■ noun / ˈəʊvəleɪ; NAmE ˈoʊvərleɪ/
1.
a transparent sheet with drawings, figures, etc. on it that can be placed on top of another sheet in order to change it :
An overlay showing population can be placed on top of the map.
2.
a thing that is laid on top of or covers sth else :
an overlay of fibreglass insulation