Do you know Arabic? Study 4:103. And all other instances about verses which contain the word prayer in it. See my other post where i numbered all the verses i could find with the word prayer in it. There are like 100 of them or something. This will also help you with understanding the Quranic context of the word.
About the meaning of the word:
ص ل و = Sad-Lam-Waw = prayer, supplication, petition, oration, eulogy, benediction, commendation, blessing, honour, magnify, bring forth, follow closely, walk/follow behind closely, to remain attached.
In a horse race when the second horse follows the first one so closely that its head always overlaps the first horse’s body that horse is called AL-MUSSALLI (i.e. the one who follows closely / remains attached).
Central portion of the back, portion from where the tail of an animal comes out, the rump.
musalla (مصلي) n. m. - 2:125
salat (صلاة) n. f. sing. - 2:3, 2:43, 2:45, 2:83, 2:110, 2:153, 2:177, 2:238, 2:277, 4:43, 4:77, 4:101, 4:102, 4:103, 4:103, 4:103, 4:142, 4:162, 5:6, 5:12, 5:55, 5:58, 5:91, 5:106, 6:72, 6:92, 6:162, 7:170, 8:3, 8:35, 9:5, 9:11, 9:18, 9:54, 9:71, 9:103, 10:87, 11:87, 11:114, 13:22, 14:31, 14:37, 14:40, 17:78, 17:110, 19:31, 19:55, 19:59, 20:14, 20:132, 21:73, 22:35, 22:41, 22:78, 23:2, 24:37, 24:41, 24:56, 24:58, 24:58, 27:3, 29:45, 29:45, 30:31, 31:4, 31:17, 33:33, 35:18, 35:29, 42:38, 58:13, 62:9, 62:10, 70:23, 70:34, 73:20, 98:5, 107:5
salawat (صلوات) nom. gen. n. plu. - 2:157, 2:238, 9:99, 22:40, 23:9
salla (صلي) vb.II m.
perf. act. 75:31, 87:15, 96:10
impf. act. 3:39, plu. neg. 4:102, plu. 4:102, tusalli (تصل) neg. 9:84, yusallee (يصلي) sing. 33:43, yusalloona (يصلون) plu. 33:56
salli (صل) impv. 9:103, salloo (صلوا) plu. 33:56, 108:2
musalleena (مصلين) pcple. act. plu. acc. gen. 70:22, 74:43, 107:4
LL, V4, p: 444, 445 ##
http://ejtaal.net/aa/#q=SLWI learned from the Quran that the Quranic context of prayer/salaat means to follow something closely. Just as the root dictionary says as well. It means everything that makes you follow God closely. And the context of prayer can be found in 4:103 which means to read the Book at scheduled times (the prayer times). This is what exactly the salaat means. After reading the Book, i prostrate as i can learn from the verse about the believers who were praying with Muhammad by turn. After they prayed, they prostrated, and another group came, and Muhammad was leading the prayer while groups coming in and out. And according to the Quranic context i believe he was reciting the Quran to them and they were reading/listening etc. after that, they prostrated and moved on.