either of a pair of wooden or metal braces on the head of a mast to support the topmast, etc
crosstree in American English
(ˈkrɔsˌtri, ˈkrɑs-)
noun
1. Nautical
either of a pair of timbers or metal bars placed athwart the trestletrees at a masthead to spread the shrouds leading to the mast above, or on the head of a lower mast to support the platform or top
2. Carpentry
a heavy crossbeam
Word origin
[1620–30; cross- + tree]This word is first recorded in the period 1620–30. Other words that entered Englishat around the same time include: contact, headline, midshipman, phosphorus, settlement