The phrase "above a letter" is correct and usable in written English.
It can be used to refer to something that is positioned or mentioned higher than a specific letter in a text or document.
Example: "Please refer to the instructions provided above a letter in the document for clarification."
Alternatives: "preceding a letter" or "over a letter".
An umlaut in the German language is a diacritical, or distinguishing, mark placed above a letter to specify the sound.
"There's nothing wrong with America's Foreign Policy that a little backbone can't cure," the headline read, above a letter in which Trump complained that Americans were being ripped off by foreign powers.
He liked to make love in the open air, and once did so (with Von Arnim) on top of the Correspondence page of the Times, above a letter denouncing West.
Subdiacritics (markings normally placed below a letter) may be placed above a letter having a descender (informally called a tail), e.g. ŋ̊, ȷ̈.
Those are the accent marks, or symbols, placed directly above a letter.
Councilman Hiram Monserrate, above, distributed a letter endorsed by 20 members urging the mayor to take "immediate action" to consider a tax for fire and police pay.
(I have sent a version of the list above in a letter to the Secretary of Education commenting on the proposed regulations).
The above is quoted from a letter written by businessmen supporting Mayor de Blasio's bid for mayoral control of NYC's public schools.
Police Commissioner Raymond W. Kelly, above, also released a letter opposing parole for the two men, while City Councilman Charles Barron said the decision should be based on their behavior in prison, not on the nature of their crime.
In his downstairs toilet, pictures of Hart with the British Army in the Balkans or standing beside an RAF fighter were interspersed with political cartoons, original artwork for anti-EU advertising and, in pride of place above the cistern, a letter from the Soviet Politburo, authorising a payment from the Kremlin to Scargill.
(The means of the continuous measure according to quintiles are shown in Table 3A,B-wrap>.) Subjects identified in the manner described above were sent a letter, with an explanation of the goals and procedures of the study, followed by a phone call, during which their eligibility was determined.
