é·clair 
(
ā-klâr
,
āklâr
′) or
e·clair 
(
ē-klâr
,
ā-klâr
,
ə-klâr
)
n. An elongated pastry filled with custard or whipped cream and usually iced with chocolate.
[French, from Old French esclair, lightning, from esclairier, to light up, from Vulgar Latin *exclāriāre, from Latin exclārāre : ex-, intensive pref.; see EX- + clārus, clear; see kelə-2 in the Appendix of Indo-European roots.]