sunup(n = noun.time) aurora, break of day, break of the day, cockcrow, dawn, dawning, daybreak, dayspring, first light, morning, sunrise - the first light of day; "we got up before dawn"; "they talked until morning"
is a kind of hour, time of day

   Sunrise. [1913 Webster]
"Such a horse as that might get over a good deal of ground atwixt sunup and sundown." [1913 Webster]

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.