spin-, spino-, spini-

(Latin: thorn, prickle; by extension, "backbone", the spinal cord)

spinalis (s) (noun) (no pl)
A group of muscles connecting the vertebrae: The spinalis dorsi, the spinalis crevicis, and the spinalis capitis are three parts of the spinalis.
spinant (s) (noun), spirants (pl)
Any agent that increases the reflex activity of the spinal cord: Doug decided to take some spirant, recommended by his doctor, to boost the muscular contraction he needed for doing his exercises.
spinate (adjective); more spinate, most spinate
Descriptive of something which is thorn-shaped or has thorns: The wild rosebush, quite spinate and blossoming gorgeously, was outside Jane's home next to the white picket fence and kept away unwanted strangers because of the many needle-like protrusions on the stems.
spination (s) (noun), spinations (pl)
The occurrence, development, or arrangement of spines on an organism: The spination on a horned toad, common in the American desert regions, is exemplified by the sharp pointed barbs or needle-like spikes which cover its flattened body.
spine (s) (noun), spines (pl)
1. Something which is similar to a backbone: A porcupine has many spines, like a ridge, following the top line of its body.
2. The vertebral column: Jack read in his biology book that the spine, or series of bones in a person's back, extends from the head to the pelvis, or from the head to the tail of an animal.
3. The pointed extension of the vertebra: The spines in triggerfish have the function of locking themselves into crevices in order to avoid being pulled out!
spineless (adjective); more spineless, most spineless
1. Referring to something without a backbone; invertebrate; without spurs, spikes or quills: The Garo spineless eel and the spineless forest lizard are examples of two spineless creatures!
2. Concerning a person who is weak in courage, willpower, energy, or vigour: Janet grew up with a mother who was quite dominant and a father who was spineless and accepted everything his wife wanted to be done.
spinescent (adjective) (not comparable)
Concerning plants that have thorns and spines: Such spinescent plants have leaf, root, or stem modifications with stiff ends, like rose prickles, and have the function of discouraging or hindering animal consumption.
spinet (s) (noun), spinets (pl)
A small compact harpsichord with only one manual: The spinet is a musical instrument which has only one keyboard and only one string per key or note.
spiniferous (adjective); more spiniferous, most spiniferous
Bearing spines, especially of plants; spiny; thorny: When little Ivy was outside in the garden and enjoying the plants, she came across a spiniferous one which pricked her finger when she touched the stem.
spiniform (adjective); more spiniform, most spiniform
Resembling or shaped like a spine: Tom went to the barber shop and came out with a new spiniform style with the top part combed up high into a thorn shaped ridge!
spinifugal (adjective) (not comparable)
Regarding the movement away from the spinal cord: A spinifugal, or efferent, nerve is one that sends impulses away from the central nervous system to the legs or arms of a person.
spinigerous (adjective) (not comparable)
Concerning plants that bear thorns or spines: A rose bush can be considered to be a spinigerous plant having such needlelike protrusions extending out from its stem.
spininess (s) (noun), spicinesses (pl)
The condition of being enveloped with thorns: The spininess of the cactus kept many animals away from it!
spinipetal (adjective) (not comparable)
Concerning nerve-impulses moving from the outer parts of the body toward the spinal cord: The spinipetal, or afferent, nerve is one that transfers messages or impulses from the legs and arms towards the central nervous system.
spinney (s) (noun), spinneys (pl)
A small area covered with trees: a copse: The spinney behind Jim's garden was a wonderful place to protect the game birds.