iadj. used of a single unit or thing; not two or more In. the 9th letter of the Roman alphabet In. the smallest whole number or a numeral representing this number In. a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks) I Chroniclesn. the first of two Old Testament books telling the history of Judah and Israel until the return from the Babylonian Captivity in 536 BC I Corinthiansn. a New Testament book containing the first epistle from Saint Paul to the church at Corinth I Esdran. an Apocryphal book consisting of a compilation from I Chronicles and II Chronicles and Ezra and Nehemiah I Johnn. the first New Testament epistle traditionally attributed to Saint John the Apostle I Kingsn. the first of two Old Testament books telling the histories of the kings of Judah and Israel I Maccabeesn. an Apocryphal book describing the life of Judas Maccabaeus I Petern. the first New Testament book traditionally attributed to Saint Peter the Apostle I Samueln. the first of two books in the Old Testament that tell of Saul and David I Thessaloniansn. a New Testament book containing Saint Paul's first epistle to the Thessalonians I Timothyn. a New Testament book containing Saint Paul's first epistle to Timothy; contains advice on pastoral matters I-beamn. girder having a cross section resembling the letter `I'