Hyphens, En Dashes, Em Dashes

Q. My reputable dictionaries give “transpacific” and “transatlantic” but not “transindian.” On its own, “his transindian voyage” would probably be ambiguous, but if I were to write “his transpacific, transatlantic, and transindian voyages were remarkable feats,” there would appear to be little risk of ambiguity. Would you consider that acceptable? If not, how should I express such a thing?

A. Yes, Chicago editors might opt for what we call “regional consistency” here by styling all three compounds in the same way rather than hyphenate “trans-Indian.” Or we might hyphenate all three, if we thought there would be any confusion about the unfamiliar “transindian.”