The word is taken from words that mean "climb."
Sometimes when I read poetry I'm frustrated by a poet who doesn't seem to realize that she's established an interesting metrical pattern that has taken me in until it's broken by a line that doesn't betray the slightest awareness of said pattern, leading me to think that I've been misreading the work, then wondering if perhaps the effect is intentional, or unintentional.
Take, for example:
Song, by Seamus HeaneyA rowan like a lipsticked girl.
Between the by-road and the main road
Alder trees at a wet and dripping distance
Stand off among the rushes.
There are the mud-flowers of dialect
And the immortelles of perfect pitch
And that moment when the bird sings very close
To the music of what happens.
-- Seamus Heaney
(Thanks to The Wondering Minstrels for this poem.)
Scansion Scan"sion, n. [L. scansio, fr. scandere, scansum, to
climb. See Scan.] (Pros.)
The act of scanning; distinguishing the metrical feet of a
verse by emphasis, pauses, or otherwise.
-- From The Collaborative International Dictionary of English v.0.48
n : analysis of verse into metrical patterns
-- From WordNet (r) 2.0
21 Moby Thesaurus words for "scansion":
Stabreim, alliterative meter, blocking, detailing, enumeration,
itemization, measure, meter, metrical pattern, metrics, numbers,
parsing, prosodic pattern, prosody, quantitative meter, resolution,
scanning, schematization, syllabic meter, vers libre,
-- From Moby Thesaurus II by Grady Ward, 1.0