From the Latin for "instill with life", it's the creation of a motion picture from a series of still images.
Animation
In an Irish tale, clever Tom captures this title magical creature who promises to bring him wealth, but deceives him instead
A leprechaun.
Adding this letter before "OK" dates back to a NASA official misunderstanding Alan Shepard during his first flight
"A"
Datum (4 letters)
Data
Achilles' one weakness was here, left dry when his mother dipped him in the River Styx
His Heel
A prehistoric drawing on stone can be called a petroglyph or this, like art sometimes seen as an urban nuisance
Graffiti
Childe Rowland, youngest son of this legendary monarch of Britain, saves his sister & brothers from an elf king
(King) Authur
The legislature of N.M., the home state of Clyde Tombaugh, has decreed this body to be a planet when it passes over the state.
Pluto
Sister-in-law (the preferred way)
Sisters-in-law
Aeschylus called this Greek's bearing of the heaven & earth "a burden not easy for his arms to grasp".
Atlas
To draw in this liberated style means without support or the guidance of instruments
Freehand
Made famous by Walt Disney, this student uses magic while his teacher is away, leading to loads of trouble
Sorcerer's Apprentice
In an annual competition, you toss a fish west over the state line from Florida to this state.
Alabama
Radius (5 letters)
Radii
In Shakespeare's play about him & Cressida, he says, "I am weaker than a woman's tear".
Trolius
From the name of an 18th century man, it's a profile portrait drawn in black
Silhouette
In this folk tale, the title barnyard trio faces off against a troll under a bridge
The Three Billy Goats Gruff
The name of this weasel relative can mean "to clear out"; in 1971 Fermilabs used one to clean the tubes of a particle accelerator
A ferret
Cherub (8 letters)
Cherubim
Phaethon tries to ride this god's chariot through the skies but isn't strong enough to control the horses
Helios
To draw with the aid of rulers, scales & compasses is this precise kind of technical drawing
Drafting
The opera "Rusalka", about a water nymph who longs to be human, is partly based on this fairy tale by H.C. Andersen
The Little Mermaid
Made from this 4-letter wood from India, the HMS Trincomalee is the oldest British warship still afloat.
Teak
Codex (7 letters--as per the Encyclopedia Britannica entry)
Codices
Suitors to Penelope struggle to string this man's bow, & it gets worse for them after that.
Odysseus