From WordNet (r) 3.0 (2006) [wn]:
EST
n 1: standard time in the 5th time zone west of Greenwich,
reckoned at the 75th meridian; used in the eastern United
States [syn: Eastern Time, Eastern Standard Time,
EST]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Est \Est\, n. & adv.
East. [Obs.] --Chaucer.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
-est \-est\ (-[e^]st). [AS. -ost, -est; akin to G. -est, -ist,
Icel. -astr, -str, Goth. -ists, -[=o]sts, Skr. -ish[.t]ha.]
A suffix used to form the superlative of adjectives and
adverbs; as, smoothest; earl(y)iest.
[1913 Webster]