Abbreviation of Alexander often used in official documents. There are almost as many entries of Alexr as the full name in the FreeCEN 1841 Census of Aberdeenshire.
The choice of abbreviation in official documents appears to be somewhat idiosyncratic. Alexr (usually recorded as Alexr) is one of the most favoured, but several others occur. A search on Alex* should find most variants and abbreviations although Alx and Alxr also occur significantly often.
NB We have noted that Alexr has occasionally been transcribed as Alexa and vice versa.