KATHISMA – 1) A kathisma (pl. kathismas or kathismata; from Grk. kathemai, “sit”) is a twentieth part of the Psalter, that is, a section conveniently readable in one sitting or session. Each of the twenty kathismas is subdivided into 3 sections called stases or antiphons. A kathisma is often followed by meditative expository hymns called sessional hymns (from Latin “sedere”, “sit”; Grk. “kathismata”, Slav.”sedalny”).
The divisions of the psalms into kathismata is as follows (using the Septuagint numbering):
| Kathisma | Stasis 1 Psalm numbers | Stasis 2 Psalm numbers | Stasis 3 Psalm numbers |
| 1 | 1-3 | 4-6 | 7-8 |
| 2 | 9-10 | 11-13 | 14-16 |
| 3 | 17 | 18-20 | 21-23 |
| 4 | 24-26 | 27-29 | 30-31 |
| 5 | 32-33 | 34-35 | 36 |
| 6 | 37-39 | 40-42 | 43-45 |
| 7 | 46-48 | 49-50 | 51-54 |
| 8 | 55-57 | 58-60 | 61-63 |
| 9 | 64-66 | 67 | 68-69 |
| 10 | 70-71 | 72-73 | 74-76 |
| 11 | 77 | 78-80 | 81-84 |
| 12 | 85-87 | 88 | 89-90 |
| 13 | 91-93 | 94-96 | 97-100 |
| 14 | 101-102 | 103 | 104 |
| 15 | 105 | 106 | 107-108 |
| 16 | 109-111 | 112-114 | 115-117 |
| 17 | 118:1-72 | 118:73-131 | 118:132-176 |
| 18 | 119-123 | 124-128 | 129-133 |
| 19 | 134-136 | 137-139 | 140-142 |
| 20 | 143-144 | 145-147 | 148-150 |
(see chart of Daily Readings from the Orthodox Psalter)
2) Also, it is the second Kanon that is sung at Matins on certain holidays.
3) Also, KATHISMA (SEDALEN) – ‘Sitting’ A hymn sung (or said) following the Third Ode of a Canon and in many other places where sitting is permitted.