Entry 2 senses · 2 variants Webster, 1913 Undated /(ŭn"dā̇*tĕd)/ · Un·da·ted · IPA /ʌnˈdeɪtɪd/ a. a. 01 a. Rising and falling in waves toward the margin, as a leaf; waved. 1. Rising and falling in waves toward the margin, as a leaf; waved.(Bot.) 02 a. Not dated; having no date; of unknown age; as, an undated letter. 1. Not dated; having no date; of unknown age; as, an undated letter.