fritillaries (pg. 52) -- Well, it's a kind of plant. That's what I get from wikipedia.
Lammas (pg. 52) -- August 1st is Lammas Day, a festival of the wheat harvest.
distraints (pg. 53) -- The legal right of a landlord to obtain a court order and seize tenants'possessions to pay for back rent.
euphroes (pg. 234) -- A suspended batten or plate of wood or brass pierced with holes through which the cords of a crowfoot are rove to suspend an awning.
Clarissa Harlowe (pg. 164) -- The heroine of one of Richardson's novels, exhibiting a female character which, as described by him, is pronounced to be "one of the brightest triumphs in the whole range of imaginative literature," is described by Stopford Brooke "as the pure and ideal star of womanhood." Interesttingly, the famous nurse Clara Barton's real name is Clarissa Harlowe Barton.
vitiated air (pg. 267) -- To reduce the value or impair the quality of.
"What's the buzz, Bob?" -- (pg. 157)
...and she had read right through Clarissa Harlowe without hanging herself (although that was sometimes only for want of a convenient hook)... -- (pg. 164)
the ladies of the town had sequi me (pg. 107) -- "Follow me"
madder (pg. 149) -- A red dye made from Rubia tinctorum.
spirketing (pg. 204) -- The planking from the waterways up to the port sills.
ultima Thule (pg. 269) -- A distant unknown region; the extreme limit of travel and discovery.
Heautontimoroumenos (pg. 283) -- The title of a Latin play by Terence, an adaptation of an earlier Greek work.
Batavia (pg. 327) -- The name of Jakarta, Indonesia (formerly Dutch East Indies) during the colonial period.
...ast illi solvuntur frigore membra... (pg. 384) -- But the other's limbs are benumbed by cold, and injured life with a groan flees beneath the shadows.
creta alba (pg. 229) -- Chalk or calcium carbonate. There's a web site for this stuff at Master and Commander medical terms
barca-Longa (pg. 253) -- A two or three-masted lugger found on the coasts of Spain and Portugal as well as more widely in the Mediterranean Sea. And here I thought it was some kind of reclining chair!
membrum virile (pg. 345) -- Uh, penis.
squills (pg. 348) -- Sea squill is a bulb which sends up a tall stalk topped by an inflorescence of small white flowers, followed by a rosette of large dull green leaves, that last until the following summer. The bulb can get quite large, reaching over five pounds in weight.