1: ἀναρίθμητος
(Strong's #382 — Adjective — anarithmetos — an-ar-ith'-may-tos )

a, negative, n, euphonic, arithmeo "to number," is used in Hebrews 11:12 .

2: μυριάς
(Strong's #3461 — Noun Feminine — murias — moo-ree'-as )

denotes either "ten thousand," or, "indefinitely, a myriad, a numberless host," in the plural, Acts 19:19; lit. "five ten-thousands," Revelation 5:11; 9:16; in the following, used of vast numbers, Luke 12:1 , AV, "an innumerable multitude," RV, "the many thousands" (RV marg., "the myriads"); Acts 21:20 , "thousands;" Hebrews 12:22 , "innumerable hosts;" Jude 1:14 , "ten thousands" (RV, marg., in each place, "myriads"). See COMPANY , THOUSANDS. Cp. the adjective murios, "ten thousand," Matthew 18:24; 1—Corinthians 4:15; 14:19 .