Calmatéma was one of the four series of the Tengwar writing system. As with all of the series it consisted of six characters in each of six tyeller or 'grades'. This particular series took its name from the first of its signs, calma (literally meaning 'lamp', but here simply representing the character 'c' or 'k').
The Calmatéma was applied either to the third or fourth series of the Fëanorian writing system. The Quenya language used the third series as the Calmatéma while Westron used the fourth. In either case half of the symbols in this series had one bow or lúva while the other half had two bows. All bows in this series curved upwards and to the left from a stem, or telco, which was either lowered, raised, or shortened. If the Calmatéma was the third series all bows were open; if the Calmatéma was the fourth series all bows were closed with a bar across their opening.
The names of the letters in Tengwar were established in Quenya and had become standardised by the Third Age. The first four signs in the third series, the Calmatéma for Quenya, were calma, anga, harma and anca, each represented a variant of the basic 'k' sound: 'k', 'g', 'ch' and 'gh', respectively. The fifth sign, noldo (earlier ngoldo), represented 'ng', while the sixth, anna was commonly used for consonantal 'y'. In Westron, where the Calmatéma was the fourth series, the first four signs had the Quenya names quesse, ungwe, hwesta and unque although they represented the same 'k', 'g', 'ch' and 'gh' sounds.