"By Any Other Name" is a second season episode of the American science fiction television series, Star Trek, first broadcast February 23, 1968, and repeated May 31, 1968. It is episode #51, production #50, with screenplay by D.C. Fontana and Jerome Bixby based on Bixby's story, and directed by Marc Daniels. The title is taken from a line spoken by Juliet in Shakespeare's play Romeo and Juliet: "that which we call a rose / By any other name would smell as sweet", a line quoted by Captain Kirk during the episode.

In this episode, beings from another galaxy commandeer the Enterprise in an attempt to return home.

The Federation starship USS Enterprise responds to a distress call from an uncharted planet. A landing party beams down to locate the source, and finds a humanoid man and woman, Rojan and Kelinda of the Kelvan Empire, who paralyze Kirk and the landing party, and order Kirk to surrender the Enterprise. Rojan tells Kirk that the Kelvans originate from the Andromeda Galaxy, and have come to find planets suitable for conquest in the Milky Way Galaxy. Because their own ship was destroyed, they need the Enterprise to make the 300-year return journey. Three other Kelvans transport aboard the Enterprise, and quickly gain control of the ship.

Hanar beams down to report to Rojan, who then orders the landing party to a holding cell. Attempting to escape, Mr Spock uses his Vulcan telepathic ability to lure Kelinda over to him, where they knock her out, and seize her control belt. Their escape is short-lived and as punishment, Rojan orders Hanar to activate his belt, reducing two of the landing team members (the security guards) to small cuboctahedral blocks of a chalk-like substance. Rojan picks up the blocks and crushes one to dust, killing Yeoman Thompson. He then transforms the other block back into human form. To create an excuse for beaming back to the ship, Spock places himself into a deep trance and Dr. McCoy requests the Kelvans allow him to take Spock to Sickbay for treatment. The Kelvans agree and transport the entire landing party and themselves to the ship. Spock makes his way to engineering with Mr Scott, and they find that they cannot get to the Kelvans' paralysis field. Instead, Spock has Scott open the control valves to the matter/antimatter system, and they inform Kirk he can destroy the Enterprise, if needed. Kirk opts not to explode the Enterprise in hopes of finding another answer.

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