photosynthetic active radiation
Merriam-Webster Online Dictionary
par (noun)1.
a) the established value of the monetary unit of one country expressed in terms of the monetary unit of another country using the same metal as the standard of value
b) the face amount of an instrument of value (as a check or note) as
(1) the monetary value assigned to each share of stock in the charter of a corporation
(2) the principal of a bond
2.
common level - equality usually used with on judged the recording to be on a par with previous ones
3.
a) an amount taken as an average or norm
b) an accepted standard , specifically a usual standard of physical condition or health
4.
the score standard for each hole of a golf course , also a score equal to par
transitive verb
to score par on (a hole)