[1885–90; pink1 + -en1]This word is first recorded in the period 1885–90. Other words that entered Englishat around the same time include: booster, foregut, lineup, retread, upsweep-en is a suffix formerly used to form transitive and intransitive verbs from adjectives(fasten; harden; sweeten), or from nouns (heighten; lengthen; strengthen)