TAROT

I was reading a description of a place where it was stated that the region was “hundreds of square miles on every side.” The square mile is a unit of area. That's the surface covered by the rectangle. The sides are miles long (miles being a unit of distance or length).

The plural of manservant is menservants.

I'm not quite sure about this one. “Different than” feels wrong to me, I would use “different from” instead. “Than” is used to make comparisons, but merely marking two objects as different isn't a comparison until you state how they differ. Looking around I've seen the phrase in some places considered nonstandard usage, others as American and still others as British. I've got nothing against “other than” but I would use “(anyplace) else but.” I think I'm losing my train of thought here. I guess I'll just try to get used to this one.

SUB v. SUB-

sub (n) abbreviation for any of a variety of words beginning “sub-” including submersible, substitute, submarine sandwich and submissive: (v) to substitute
sub- (prefix) under, of lower degree, a smaller division of

When I see “a sub sect of Christianity,” my mind starts thinking of early Christians praying in the nave of their submersible and torpedoing Roman galleys, either that, or taking the whole “turn the other cheek” thing to a kinky sex place. Use sub-sect or subsect and I'll follow your line of thought without a hiccup.
On the web, I'll occasionally see mention of a “sub forum” which is similarly distracting. Sub-forum or subforum is better.
Take a chance, ignore the little red squiggles and make the neologism.

CHITIN/CHITON

chitin (n) a rigid, semi-transparent substance forming the exoskeleton of insects etc.
chiton (n) a tunic worn in ancient Greece

The demon stalked closer, the chitin of its legspears crackling against the stone floor.
She donned her finest chiton for the gathering.

CHOCKING/CHOKING

chock (v) to secure with wedges: chocked, chocking
choke (v) to stop the breath of, obstruct, clog, strangle: choked, choking

The maintenance worker chocked the wheels of the aircraft in place. The worker was chocking the wheels.
The passage through the ruins was choked with vines.
The choking fumes of the gas drifted across the battlefield.

CONTINGENT ON v. PRECLUDED BY

contingent (adj) conditional, possible, accidental
preclude (v) to make impossible, exclude

When making the budget, they set aside a little something for contingent expenses.
Whether the wedding will be outside is contingent on the weather.
The outdoor festivities were precluded by the driving rain.
His physical infirmities precluded his service in the infantry.

DEMUR/DEMURE

demur (v) to take exception, object (esp. on principle), to hesitate: (n) an objection
demure (adj) shy, reserved, modest

When he heard that he was being considered for the job, he began looking for reasons to demur.
The princess was renowned for her demure manner.

FORTH/FOURTH

forth (adv) onward, forward, away
fourth (adj) ordinal of number four, being of four equal parts

Go forth and conquer.
Now we come to the fourth item on the agenda.

GROPING/GROUPING

grope (v) to search for blindly, to manhandle: groping
group (v) to arrange or sort: grouping

They dashed down the corridor, avoiding the groping tentacles.
Her shots hit the target in a tight grouping that would have fit under a quarter.

INFINITY/INFINITELY

infinity (n) something that has no end
infinitely (adv) endlessly

I'm sure that you have an infinity of questions.
That was done in infinitely poor taste.

ORDINANCE/ORDNANCE

ordnance (n) artillery, military stores
ordinance (n) a decree, a public regulation

If you need support, you know how to call for the heavy ordnance.
The prisoner was found on the street after curfew in direct disobedience of your ordinance.

SCRAPING/SCRAPPING

scraping (n) the act of rubbing or removing the outer layer, the sound of same, the part removed (usu. scrapings)
scrap (v) to discard, to fight: scrapping

The crime scene technician took a scraping of the orange residue.
The gardener turned the hose on the scrapping dogs.

STRIPED/STRIPPED

striped (adj) having bands (of colour etc.)
stripped (adj) having had covering or equipment removed

He was wearing a striped t-shirt.
The stripped car was rusting on the lawn.

WEATHER/WHETHER

weather (n) the atmospheric state: (v) to expose to the outdoors, to change or endure
whether (conjunction) used to introduce alternatives or a single alternative

The weather started getting rough. The tiny ship was tossed.
I'm coming in whether you're ready or not.