arbor
UK[ˈɑːbə]US[ˈɑːrbər]
n
A shady garden shelter or recess, often made of latticework on which plants such as climbing shrubs or vines are grown.
n
A spindle, axle, or rotating shaft in a machine, especially one that supports a rotating cutting tool or workpiece.
Etymology
The English word 'arbor' has a dual meaning, both tracing back to Latin but from distinct roots. The primary meaning of a garden shelter derives from Latin 'arbor' or 'arbos', meaning 'tree'. This Latin term itself is of uncertain origin, though it may be related to the Proto-Indo-European root h₃erdʰ- ('high, to grow'). The logic of the semantic shift from 'tree' to a 'tree-like' shaded structure is clear. The secondary, mechanical meaning of a shaft or spindle comes from a different Latin word, 'arbor', meaning 'a beam or mast', which is likely a separate derivation from the same PIE root, emphasizing the concept of a tall, supporting pole. The convergence of these two distinct but related Latin words into a single English spelling is a historical accident of borrowing.
Analysis
The word 'arbor' is a simplex loanword from Latin. Its spelling and form were adopted directly into English without segmentation into smaller meaningful English morphemes.
Examples
They sat in the rose-covered arbor to enjoy the cool evening.
The lathe operator carefully secured the workpiece to the arbor.
The old garden's most charming feature was a wooden arbor draped with wisteria.