arachno-, arachn- +

(Greek: spider; the arachnoidea; when used in medicine this Greek element refers to a membrane, veins, or any web-like structure in the body)

arachnactis
A planktonic larva of tube anemones (Ceriantharia).
Arachne
Despite the generally adverse feelings of many people towards spiders, they have in many parts of the world become a part of folk myth and legend, perhaps more so than any other anthropod.

The very name Arachnida, the arthropod class to which the spiders belong, is derived from the story of the Greek maiden from Lydia, Arachne, who was so skilled as a weaver that she had the audacity to challenge the goddess Athena to a weaving contest.

Athena accepted the challenge and wove a tapestry depicting the majesty of the gods while Arachne wove one depicting the gods' amorous adventures or love affairs.

Enraged at the perfection of her rival's work, Athena tore it to shreds, which so upset the maiden that she hanged herself. Out of pity, Athena is said to have loosened the rope from around Arachne's neck which was turned into a cobweb, and Arachne was changed into a spider, doomed to spend the rest of her life weaving.

Spiders of the World by Rod & Ken Preston-Mafham;
Facts On File Publication; New York; 1984; page 14.
arachnean
Resembling a spider's web.
arachnephobia, arachnophobia, arachneophobia
An excessive fear of spiders. Some arachnophobics fumigate their homes on a regular basis, wash all fruits and vegetables, and check incoming bags and other containers where spiders might be hiding.

They are usually unable to go on a picnic or stay in strange hotels or houses, and they are usually checking around themselves when they are outside. Some people have been known to become physically sick at the sight of a spider.

Scribe is frightened by the shadow of a spider
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Sometimes she is the admired heroine deserving of reverence, at times the recipient of men's souls after death, and at other times the villain who induces fear, abhorrence and sinister forebodings.

—W.S. Bristowe, The World of Spiders
arachnid
A member of Arachnida, a class of arthropods, including scorpions, spiders, ticks, and mit4s.

They are distinguished from insects by having four pairs of walking legs and by having the head and thorax in a single prosoma.

Arachnida
A class of arthropods of the subphylum Chelicerata, that includes mites, ticks, spiders, scorpions, and related forms.

Many of the most important parasites and vectors of human and animal pathogens are included in this large assemblage.

More about Arthropoda

Along with the insects, crustaceans, centipedes, and millipedes; spiders are members of that group of animals without backbones referred to as the Arthropoda, literally the "jointed-limbed" animals.

Clearly they lack a backbone and instead have an external skeleton, called an exoskeleton, which has some similarities to a suit of armor; it is tough and fairly rigid and the muscles are attached to it internally.

Like the vertebrate skeleton, that of the arthopods is designed as a compromise between rigidity, to provide support and protection for the soft, delicate internal organs, and flexibility, to allow for ease of movement.

Spiders of the World by Rod & Ken Preston-Mafham;
Facts On File Publication; New York; 1984; page 16.
arachnidan
Any of various arthropods of the class Arachnida, such as spiders, scorpions, mites, and ticks, characterized by four pairs of segmented legs and a body that is divided into two regions, the cephalothorax and the abdomen.
arachnidial
Pertaining to the Arachnida.
arachnidian
Relating to, or resembling, a member of the class Arachnida.
arachnidism
A morbid condition resulting from the bite of an arachnid, that may include ascending motor paralysis and destruction of peripheral nerve endings.

Also called spider poisoning, arachnoidism, and araneism.

arachnidium
1. The glandular organ in which the material for the web of spiders is secreted.
2. The spinning apparatus of a spider, including spinning glands and spinnerets.
arachnidologist (s) (noun), arachnidologists (pl)
Someone who specializes in the study of spiders.
arachnidology (s) (noun), arachnidologies (pl)
The study of spiders by entomologists and arachnidologists.
arachnidous
Of the nature of the Arachnid.
arachniform
Resembling, or in the form of, a spider web.

The most striking physical properties of spider silk are its strength and elasticity. It has been found that a thread .01 centimetre in diameter will support a weight of 80 grammes before breaking, and will stretch by over twenty per cent of its original length.

—Keith C. McKeown; Spider Wonders of Australia;
Halstead Printing; Sydney, Australia; 1936; page 218.

Cross references of word families that are related directly, or indirectly, to: "spider; arachnoidea": acaro-; arano-; mite, mites.