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ed

Pronunciation: (ed), [key]
—n. Informal.
education: a course in driver's ed; adult ed.

Ed

Pronunciation: (ed), [key]
—n.
a male given name, form of Edgar or Edward.

ED₅₀,

Pharm.
effective dose for 50 percent of the group; the amount of a drug that is therapeutic in 50 percent of the persons or animals in which it is tested.

-ed

a suffix forming the past tense of weak verbs: he crossed the river.

-ed

a suffix forming the past participle of weak verbs (he had crossed the river), and of participial adjectives indicating a condition or quality resulting from the action of the verb (inflated balloons).