"双手合抱量" can be translated into English as "the measurement taken by clasping both hands around (an object)" or more concisely as "the measurement by hand-span (when clasping)".
However, in more technical or specific contexts, if referring to a traditional or non-standardized way of measuring circumference (like wrapping hands around a tree trunk or a similar object), it might be described as "the circumference measured by clasping hands around" or simply "hand-clasp circumference measurement".
For a more general and simpler expression in everyday contexts, "the measurement by clasping hands" could suffice, though it might not be as precise in technical discussions.
If you're looking for a term that might be more widely recognized in certain fields (like forestry or traditional crafts), you might need to adapt based on the specific usage or create a new compound term if none exists.
A straightforward and commonly understandable translation would be: