forenoon(n = noun.time) morn, morning, morning time - the time period between dawn and noon; "I spent the morning running errands"
is a kind of period, period of time, time period
is a part of day, daylight, daytime
has parts: early-morning hour

   The early part of the day, from morning to meridian, or noon. [1913 Webster]

forenoon, n. Naut. or Law or archaic the part of the day before noon.

N  morning, morn, forenoon, a, m, prime, dawn, daybreak, dayspring, foreday, sunup, peep of day, break of day, aurora, first blush of the morning, first flush of the morning, prime of the morning, twilight, crepuscule, sunrise, cockcrow, cockcrowing, the small hours, the wee hours of the morning, spring, vernal equinox, first point of Aries, noon, midday, noonday, noontide, meridian, prime, nooning, noontime, summer, midsummer, matin, matutinal, vernal, at sunrise, with the sun, with the lark, when the morning dawns, at shut of evening flowers, entre chien et loup, flames in the forehead of the morning sky, the breezy call of incense-breathing morn.