spar 1 
(spär)
(spär)n.
1. Nautical A wooden or metal pole, such as a mast, boom, yard, or bowsprit, used to support sails and rigging.
2. A usually metal pole used as part of a crane or derrick.
3. A main structural member in an airplane wing or a tail assembly that runs from tip to tip or from root to tip.
tr.v. sparred, spar·ring, spars
1. To supply with spars.
2. Obsolete To fasten with a bolt.
[Middle English sparre, rafter.]