Entry 2 senses · 2 variants Webster, 1913 Midday /mĭd'-dāˌ/ · Mid·day · IPA /mɪdˈdeɪ/ n. a. 01 n. The middle part of the day; noon. 1. The middle part of the day; noon. 02 a. Of or pertaining to noon; meridional; as, the midday sun. 1. Of or pertaining to noon; meridional; as, the midday sun.