Proper noun
Pss.
Abbreviation of Psalms.
It is admitted by all that Pss. 9 and 10 were originally a single acrostic poem; they have been wrongly separated by Massorah, rightly united by the Septuagint and Vulgate. Source: Internet
Some psalms exhort the worshipper to sing (e.g. Pss. 33:1-3; 92:1-3; 96:1-3; 98:1; 101:1; 150). Source: Internet