I1N1T1E1R1C3A1L1A1T1E1
13 points
INTERCALATE is validvalid
to insert between regular or preexisting elements of a list [v INTERCALATED, INTERCALATES, INTERCALATING] : INTERCALATION [n]
to insert (as a day) in a calendar [v INTERCALATED, INTERCALATING, INTERCALATES]