Wordorigins.org

These two interjections have both been popularized by cartoons.

The first, doh, has been made famous by Homer Simpson, but he was not the first to use it. That honor goes to James Finlayson, who appeared with the comedians Laurel and Hardy in several films. This dialogue is from the 1931 Pardon Us, Laurel and Hardy’s first full-length film:

Professor Finlayson: How many times does three go into nine?
Stan: Three times.
Finlayson: Correct.
Stan: And two left over.
Finlayson (to Ollie): What are you laughing at?
Ollie (snickering): There’s only one left over.
Finlayson: D-ohhhh!

Triskaidekaphobia is the fear of the number thirteen. It began life, and has pretty much remained, a psychological jargon term. Its first appearance in English is in Isador Coriat’s 1911 Abnormal Psychology.

Like many scientific terms, this one is a modern invention based on Greek roots. Triskaideka, or τρεισκαιδεκα, is Greek for thirteen, to which the suffix -phobia, or -φοβία, meaning fear, is added.

(Source: Oxford English Dictionary, 2nd Edition)

The online OED has just published another quarterly update, revising the entries from quittal to ramvert. New words added to the dictionary include subprime, adj.; wantaway, adj.; cookie cutter, n. & adj.; and radiophysics, n.¹; this last referring to branch of physics dealing with ionizing radiation; the original entry, which is now radiophysics, n.², refers to the physics of radio waves.

Editor John Simpson comments on the changes here.

This name for the American South first appears in 1859 in the lyrics of a minstrel song. The etymology is uncertain, but it is most likely a reference to the Mason-Dixon Line, the border between Pennsylvania and Maryland delimited by those eponymous surveyors.

The first recorded use of the of Dixie is from the song Johnny Roach, by Daniel D. Emmett, first performed in February 1859:

Gib me de place called Dixie land,
Wid hoe and shubble in my hand.

Deadline is currently almost exclusively used to mean a time by which a task must be accomplished, but this was not always so. In the past, deadline had a variety of meanings, all related to a boundary for which there was a severe penalty for crossing.

The oldest of these uses dates to the American Civil War and refers to a line drawn around a military prison outside of which a prisoner could be shot, a literal “dead” line. From the Congressional Record of 12 January 1864:

The “dead line,” beyond which the prisoners are not allowed to pass.