Webster’s Revised Unabridged Dictionary · 1913
Livelong
Live′long′, a. [For lifelong. Cf. Lifelong.] 1. Whole; entire; long in passing; — used of time, as day or night, in adverbial phrases, and usually with a sense of tediousness.
The obscure bird Clamored the livelong night. Shak.
How could she sit the livelong day, Yet never ask us once to play? Swift.
2. Lasting; durable. [Obs.]
Thou hast built thyself a livelong monument. Milton.