(baseball) a measure of a pitcher's effectiveness; calculated as the average number of earned runs allowed by the pitcher for every nine innings pitched
a major division of geological time; an era is usually divided into two or more periods
a period marked by distinctive character or reckoned from a fixed point or event
Abbreviation for Engine Room Artificer - rank in Royal Navy
FIRST
before anything else; "first we must consider the garter snake"
ranking above all others; "was first in her class"; "the foremost figure among marine artists"; "the top graduate"
the initial time; "when Felix first saw a garter snake"
serving to begin; "the beginning canto of the poem"; "the first verse"
prominently forward; "he put his best foot foremost"
serving to set in motion; "the magazine's inaugural issue"; "the initiative phase in the negotiations"; "an initiatory step toward a treaty"; "his first (or maiden) speech in Congress"; "the liner's maiden voyage"
before another in time, space, or importance; "I was here first"; "let's do this job first"
preceding all others in time or space or degree; "the first house on the right"; "the first day of spring"; "his first political race"; "her first baby"; "the first time"; "the first meetings of the new party"; "the first phase of his training"