\v'N'moves down. The default scaling factor is vs.
\v'-N'Negative offsets move up.
\v'|N'To move to an absolute position N, move relative by the distance from here to N.
\rmoves up one em in troff, one v in nroff.
\u text \dmoves up half a v, then prints text, then moves down half a v again. (It works the other way 'round, to.)
\h'N'moves horizontally. The default scaling factor is ems.
\h'-N'Negative offsets move to the left.
\h'|N'To move to an absolute position N, move relative by the distance from here to N.
\w'x'is the width of x in basic units. The idiom for moving by the length of a word is
\zxprints x and then doesn't move.