("Goibaut" is the preferred spelling: that is how he signed his name.)

Pycnometer is the preferred spelling in modern American English usage.

The style of preferred spelling, punctuation, hyphenation and indentation used in a publishing house or by a particular publication to ensure consistent typesetting.

I would be the last one to stake anything worthwhile on the statistical base used for determining the "preferred" spellings in dictionaries.

Kauffman (not Kauffmann) is the preferred spelling of her name; it is the form she herself used most in signing her correspondence, documents and paintings.

Khwe is the preferred spelling of the Khwe people, also commonly written Khoe.

Racket is the preferred spelling in tennis.

The preferred spelling in modern times is "Lashkar."

Demonbreun Street in Nashville shows the preferred spelling.

In Ireland, the preferred spelling is Cillian; the name appears thus in the Irish liturgical calendar.