VOCABULARY:
Sefer - Book
Mizmor - Psalm : Psalmos(Greek) Psalmus(Latin)
Pasuk - Verse
Sefer Tehillim contains 150 Mizmors.
Divided into 5 sections (books):
Psalms enumeration in the Greek translation (Septuagint) is slightly different from the Hebrew Original:
Psalms 9 and 10 combined into one; psalms 114 and 115 were also combined
Psalms 116 and 147 divided in two.
But in the end the Septuagint and the original versions contain 150 Psalms anyway.