Kalamos is a Greek word meaning "reed", from which comes stories of the Greek mythological figure Kalamos, the son of Maiandros (aka Meander), god of the Meander River.

Kalamos is also the name of a small Greek island of about 600 residents in the Ionian Sea.

The story, told in Nonnus's Dionysiaca, tells of the love of two boys, Karpos and Kalamos. Karpos is drowned, and in his grief Kalamos is turned into a water reed. It has been suggested that this myth inspired the title for Walt Whitman's "Calamus" poems in Leaves of Grass.

Cognates can be found in Sanskrit (kalama, meaning "reed" and "pen" as well as a sort of rice) and Latin (calamus), suggesting the word originates in Proto-Indo European, the parent language of the three. The Arabic word qalam (meaning "pen" or "reed pen") is likely to have been borrowed from one of these languages in antiquity, or directly from Indo-European itself.

From the Latin calamus come a number of modern English words:

• calamus (aka Sweet Flag), a wetland plant.
• calamari, meaning "squid", via the Latin calamarium, "ink horn" or "pen case", as reeds were then used as writing implements;
• calumet, another name for the Native American peace pipe, which was often made from a hollow reed;
• shawm, a medieval oboe-like instrument (whose sound is produced by a vibrating reed mouthpiece);
• chalumeau register, the lower notes of a clarinet's range (another reed instrument).