Latin-script digraph
Ij
IJ, also encountered as Unicode compatibility characters IJ and ij, is a digraph of the letters i and j.
Occurring in the Dutch language, it is sometimes considered a ligature, or a letter in itself. In most fonts that have a separate character for ij, the two composing parts are not connected but are separate glyphs, which are sometimes slightly kerned.
Text adapted from Wikipedia, CC BY-SA 4.0. Photograph: Johann Jaritz (see Commons), Wikimedia Commons.