Source: Change Vision ( Michael Chonoles)
The spec uses both.
The spelling with the space predominates.
ISO probably has a preference. Their document How to write standards http://www.iso.org/iso/how-to-write-standards.pdf use "subclauses" as one word.
However some of their actual documents use either "subclauses" or "sub-clauses". I didn't see anyone using "sub clauses" and their documents appear to be internally consistent.
Reported: UML 2.5 — Wed, 24 Feb 2016 03:15 GMT
Updated: Wed, 24 Feb 2016 07:32 GMT
UMLR — Decide whether the document divisions are "sub clauses" or "subclauses"
- Key: UMLR-663
- OMG Task Force: UML 2.6 RTF