Q

quarterpace (noun)
A staircase landing where the stairs turn at a right angle. (MW)
See:  halfpace

quire (noun)
A measure of paper quantity:  25 (formerly 24) sheets of paper; one twentieth of a ream (500 sheets). (Wikipedia)

quixotic (adjective)
Exceedingly idealistic; unrealistic and impractical. (OD)

𓐵

P <=> R