On grammatical class:

ma'o
convert letteral string or other mathematical expression (mex) operand to mex operator.

In definition:

cmavrma'o
x1 is the selma'o "MAhO".

In notes:

mekseia
x1 is a part of Lojban text representing rule 'mex-operator' according to the first edition of the book 'The Complete Lojban Language'.