The metrical foot is the basic unit of meter. The most common metrical feet and their patterns of stressed and unstressed syllables are as follows:
iamb: X /
trochee: / X
anapest: X X /
dactyl: / X X
spondee: / /
pyrrhic: X X
The meter of a poem is determined by the predominant metrical foot, and by the number of feet per line that predominates in the poem. The following terms indicate the number of feet per line:
monometer: one foot per line
dimeter: two feet per line
trimeter: three feet per line
tetrameter: four feet per line
pentameter: five feet per line
hexameter: six feet per line
heptameter: seven feet per line
octameter: eight feet per line
Although there are terms for longer lines, the fact is that if a line gets much beyond eight feet (and even if it approaches eight feet), it tends to break into two shorter lines, simply because the speaker must pause for breath.

http://nv.essortment.com/metricalfoot_rxjm.htm

ofTroy: Your whitewashed observations were most edifying. Sounds as though our brains hold a contortionist version of ourselves.

Best regards,
Westwords-Ho!