Nomina sacra

In a few early cases, an alternate practice is seen of abbreviation by suspension, meaning that the initial two letters (at least) of the word are used; e.g., the opening verses of Revelation in 𝔓18 write Ἰησοῦς Χριστός (Jesus Christ) as ΙΗ ΧΡ.

It is evident that the use of nomina sacra was an act of reverence rather than a purely practical space-saving device,[4]: 100, 104-106  as they were employed even where well-established abbreviations of far more frequent words such as and were avoided,[4]: 101  and the nomen sacrum itself was written with generous spacing.

Biblical scholar Larry Hurtado has suggested Greek numerals as the origin of the overline spanning the nomen sacrum, with ΙΗ, the ordinary way of writing "18", being taken as reminiscent of a suspended form of ΙΗΣΟΥΣ (Jesus).

[7] Linguist George Howard argues that κς (κύριος) and θς (θεός) were the initial nomina sacra, created by non-Jewish Christian scribes who "found no traditional reasons to preserve the tetragrammaton" in copies of the Septuagint.

Hurtado, following Colin Roberts, rejects that claim in favour of the theory that the first was ιη (Ἰησοῦς), as suggested in the Epistle of Barnabas, followed by the analogous χρ (Χριστός), and later by κς and θς, at about the time when the contracted forms ις and χς were adopted for the first two.