earmark (n.) Look up earmark at Dictionary.com
late 15c., from ear (n.1) + mark (n.1). Originally a cut or mark in the ear of sheep and cattle, serving as a sign of ownership (also a punishment of certain criminals); first recorded 1570s in figurative sense "stamp of ownership."
earmark (v.) Look up earmark at Dictionary.com
1590s, "to identify by an earmark," from earmark (n.). Meaning "to set aside money for a special purpose" is attested by 1868. Related: Earmarked; earmarking.