upper-case letter is a noun meaning "one of the large alphabetic characters used as the first letter in writing or printing proper names and sometimes for emphasis". It carries one recorded sense.
one of the large alphabetic characters used as the first letter in writing or printing proper names and sometimes for emphasis
“printers once kept the type for capitals and for small letters in separate cases; capitals were kept in the upper half of the type case and so became known as upper-case letters”
Definitions, synonyms and semantic relations for upper-case letter come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.