Ĥ, or ĥ is a consonant in Esperanto orthography, representing a voiceless velar fricative [x] or voiceless uvular fricative [χ]. Its name in Esperanto is ĥo (pronounced /xo/).
Contents
It is also used in the revised Demers/Blanchet/St Onge orthography for Chinook Jargon.
In the case of the minuscule, some fonts place the circumflex centred above the entire base letter h, others over the riser of the letter, and others over the shoulder.
Ĥ is the eleventh letter of the Esperanto alphabet. Although it is written as hx and hh respectively in the x-system and h-system workarounds, it is normally written as H with a circumflex: ĥ.
Reported demise
Ĥ was always the least used Esperanto letter (though it usually has more dictionary entries than ĵ), and most of its uses are in Greek etyms, where it represented chi. Since the latter is pronounced [k] in most languages, neologistic equivalents soon appeared in which "ĥ" was replaced by "k", such as teĥniko → tekniko ("technology") and ĥemio → kemio ("chemistry"). Some other ĥ-replacements followed unusual patterns, such as ĥino → ĉino ("Chinese [person]").
These additions and replacements came very early and were in general use by World War I. Since then the imminent demise of ĥ has been often discussed, but has never really happened. There are very few modern ĥ-replacements, notably koruso for ĥoro ("chorus"). Some ĥ-words are preferred to existing replacements (old or new), such as ĥaoso vs. kaoso ("chaos").
Several words commonly use ĥ, particularly those of non-Greek etymology (ĥano ("khan"), ĥoto ("jota"), Liĥtenŝtejno ("Liechtenstein"), etc.) or those in which there is another word that uses "k" in that context. The latter include:
Other uses
An Italian italo disco singer from the 1980s had the ĥ in his stage name "Cĥato".
In quantum mechanics, Ĥ is sometimes used to represent the Hamiltonian operator, especially in the Wheeler–DeWitt equation.