pace vs pacer

pace and pacer both are nouns.

Word	Noun	Adjective	Verb	Adverb
pace	Yes	No	Yes	No
pacer	Yes	No	No	No

pace (noun)	pacer (noun)
a step in walking or running	a horse trained to a special gait in which both feet on one side leave the ground together
the relative speed of progress or change	a horse used to set the pace in racing
a unit of length equal to 3 feet; defined as 91.44 centimeters; originally taken to be the average length of a stride
the distance covered by a step
the rate of moving (especially walking or running)
the rate of some repeating event