/ ˈkɒnstənt; NAmE ˈkɑːn-/ adjective , noun
■ adjective
1.
[ usually before noun ] happening all the time or repeatedly :
constant interruptions
a constant stream of visitors all day
Babies need constant attention.
This entrance is in constant use.
2.
that does not change
SYN fixed :
travelling at a constant speed of 50 m.p.h.
■ noun
( technical ) a number or quantity that does not vary
OPP variable
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WORD ORIGIN
late Middle English (in the sense staying resolute or faithful ): from Old French , from Latin constant- standing firm, from the verb constare , from con- with + stare stand. The noun senses date from the mid 19th cent.