adverb
technical :exactly straight down or up :in a perfectly vertical position
US informal + old-fashioned :to a complete degree :completely
informal :exactly, directly
adjective
[more ~; most ~] technical :exactly vertical :standing perfectly straight and not leaning in any way
verb
plumbs; plumbed; plumbing
[+ obj] a literary :to examine (something) in a careful and complete way in order to understand it
to experience or reach (something)
US
to install pipes for sinks, toilets, etc., in (a building or room)
to connect (something, such as a sink) to a water supply
plumb in
[phrasal verb] chiefly Brit plumb (something) in or plumb in (something) :to connect (something) to a water supply