Lewis & Short

1. mĕrenda, ae, f. [mereo, q. v.], an afternoon luncheon, taken between four and five o’clock (ante- and post-class.): merendam antiqui dicebant pro prandio, quod scilicet medio die caperetur, Paul. ex Fest. p. 123 Müll.: merenda dicitur cibus post meridiem qui datur, Non. 28, 32; Plaut. Most. 4, 2, 49; Afran. ap. Non. 28, 33: serae hora merendae, Calp. Ecl. 5, 60; cf. Isid. Orig. 20, 2, 12.
Also of feed or medicine for a beast: Cyprio bovi merendam, Ennius cum dixit, significat id, quod solet fieri in insulā Cypro, in quā boves humano stercore pascuntur, Paul. ex Fest. p. 59 Müll. (sola, v. 2 Vahl. p. 164).