I'll start us off. Inspired by our own pensateomnia, the current word of the day is lacuna.
noun \lə-ˈkü-nə, -ˈkyü-\
plural la·cu·nae also la·cu·nas
Definition of LACUNA
: a blank space or a missing part : gap <the evident lacunae in his story — Shirley Hazzard>; also : deficiency 1 <despite all these lacunae, those reforms were a vast improvement — New Republic>
: a small cavity, pit, or discontinuity in an anatomical structure