What item of clothing shares its name with a timber joint?

MITRE JOINT.

For a mitre joint, the ends of two pieces of wood are under cut at a 45 degree angle. The mitre, which is only marginally stronger than the butt, is used widely for appearance sake as the joint conceals the exposed end grain of both pieces of timber.

They require precision 45 degree cuts so that the right angle can be accurately made, it is recommended that the angles are cut using a power circular saw with a suitable guide of jig for accuracy. Using a Jig Saw or handsaw are liable to produce some inaccuracies which will ruin the visual appearance and give a weak joint as the adjacent pieces of timber will not fit very well.

The mitre, also spelled miter , is a type of headgear now known as the traditional, ceremonial head-dress of bishops and certain abbots in the Roman Catholic Church, the Anglican Communion, some Lutherans, and also bishops and certain other clergy in the Eastern Orthodox Church, Eastern Catholic Churches and the Oriental Orthodox Churches.

http://diydata.com/techniques/timber_joints/box_joints/box_joints.php

https://en.wikipedia.org/wiki/Mitre

Or the SCARF joint http://www.timberbestpractice.org.uk/tbpp/ATR/joints/f_ilock4.htm

"The scarf joint is designed to join timber members end-to-end and is still used in some timber structures. Scarf joints lap one member over another, maintaining a uniform cross-section. Many ways of achieving this were developed but the splayed scarf is the one which has survived.

The splayed scarf is normally three to six times as long as the depth of the members though glued scarfs may have length to depth ratios as shallow as 1 in 12.

A straight splay provides no interlock between members and depends entirely on pins or glues to avoid displacement. The weak 'feather end' at the point of the splay can be damaged during construction.

The joint is improved by forming vertical abutments at the end of each splay, by stepping the splay and ultimately by incorporating folding wedges to drive the surfaces of the joint together. Scarf joints are often secured with bolts extending vertically through the joint."

Direct quote 'cos I couldn't describe it, but look at the pics - way better.