We can frequently find this word in the first sentence of the sutta.
The word eka is an adjective that can mean:
1. same, certain, unknown (for the indefinite article);
2. one (in the singular);
3. some (in plural).
DN22 Mahasatipatthana Sutta CSCD372/PTS2.290
Eva.m me suta.m - eka.m samaya.m bhagavaa kuruusu viharati
thus / by me / have heard / one / time / the Blessed One / in Kuru
Thus have I heard - at one time, the Blessed One lives in the Kuru country,
kammaasadhamma.m* naama kuruuna.m nigamo (hoti/atthi).
Kammasadhamma / named / of Kuru / market town (there is)
there is a (Kuru's) market town named Kammasadhamma.
- eva.m (adv.) thus, in this way.
- me (ins. of aha.m, I) by me.
- suta.m (p.p. of su.naati) have heard.
- samaya.m (m.) time.
- bhagavaa (nom. sing. of bhagavant) the Blessed One, Buddha.
- kuru (proper noun, state or country) Kuru.
- kuruusu (loc.) in Kuru.
- viharati (v.) lives, dwells.
- kammaasadhamma (proper noun) Kammasadhamma.
- naama (adj.) having the name of.
- kuruuna.m (gen.) of Kuru.
- nigama (m.) market town.
*The Thai version has kammaasadamma.m.
Word List 1:
01. ca | na
| ti | pe
| vaa | kho
| bhikkhave | hoti
| dhammo | so
11. uppajjati | paccayo
| tattha | pa.ticca |
ta.m | dhammaa |
dhamma.m | te |
eva.m | pana
21. tassa | no |
eka.m | bhikkhu |
tii.ni | tesa.m |
me | bhagavaa |
31. aya.m | atha |
tena | ya.m |
hetupaccayaa | nava | atthi | yo | ye |
41. bhikkhuu | aamantaa | citta.m | khandhaa | yassa | ruupa.m | pańca |
viharati | aavuso | vuccati