"thing that erases writing," 1790, American English, agent noun from erase. Originally a knife for scraping off the ink. As a rubber product for removing pencil marks, from 1858.
English agent noun ending, corresponding to Latin -or. In native words it represents Old English -ere (Old Northumbrian also -are) "man who has to do with," from Proto-Germanic *-ari (cognates: German -er, Swedish -are, Danish -ere), from Proto-Germanic *-arjoz. Some believe this root is identical with, and perhaps a borrowing of, Latin -arius (see -ary).
Generally used with native Germanic words. In words of Latin origin, verbs derived from past participle stems of Latin ones (including most verbs in -ate) usually take the Latin ending -or, as do Latin verbs that passed through French (such as governor); but there are many exceptions (eraser, laborer, promoter, deserter; sailor, bachelor), some of which were conformed from Latin to English in late Middle English.
The use of -or and -ee in legal language (such as lessor/lessee) to distinguish actors and recipients of action has given the -or ending a tinge of professionalism, and this makes it useful in doubling words that have a professional and a non-professional sense (such as advisor/adviser, conductor/conducter, incubator/incubater, elevator/elevater).
1930, "elastic rope," probably an extended use of the identical word used in late 19c. British schoolboy slang for "rubber eraser;" this probably is more or less onomatopoeic, from notions of bouncy + spongy. First record of bungee jumping is from 1979.
mid-14c., pencel, "an artist's small, fine brush of camel hair," used for painting, manuscript illustration, etc., from Old French pincel "artist's paintbrush" (13c., Modern French pinceau) and directly from Medieval Latin pincellus, from Latin penicillus "painter's brush, hair-pencil," literally "little tail," diminutive of peniculus "brush," itself a diminutive of penis "tail" (see penis).
Small brushes formerly were used for writing before modern lead or chalk pencils. Sticks of pure graphite (commonly known as black lead) were used for marking things in England from the mid-16c., and the wooden enclosure for them was developed in the same century on the Continent. This seems to have been the time the word pencil was transferred from a type of brush to "graphite writing implement." The modern clay-graphite mix was developed early 19c., and pencils of this sort were mass-produced from mid-19c. Hymen L. Lipman of Philadelphia obtained a patent for the pencil with an attached eraser in 1858.
Derogatory slang pencil-pusher "office worker" is from 1881 (pen-driver, jocular for "clerk, writer," is from 1820); pencil neck "weak person" first recorded 1973. Pencil-sharpener as a mechanical device for putting the point on a lead pencil is by 1854.
And here is a new and serviceable invention—a pencil sharpener. It is just the thing to carry in the pocket, being no larger than a lady's thimble. It sharpens a lead pencil neatly and splendidly, by means of a small blade fitted in a cap, which is turned upon the end of a pencil. A patent has been applied for. Made by Mr. W. K. Foster, of Bangor. ["The Portland Transcript," Portland, Maine, Sept. 30, 1854]