A number of words are conventionally abbreviated by Byzantine scribes; the abbreviation is indicated with a horizontal line above the abbreviated word. Some are proper names (Δαυίδ, Ἱερουσαλήμ, Ἰησοῦς, Ἰσραήλ); most are common nouns; but all have theological significance in a Christian context, hence the name nomina sacra which has been used since the early 20th century to designate this convention. The main nomina sacra are as follows:
These nomina sacra may be inflected, e.g. Α͞Ν͞Ο͞Υ = αν(θρωπ)ου, Ι͞Ν = ι(ησου)ν, Κ͞Υ = κ(υριο)υ, Μ͞Ρ͞Α = μ(ητε)ρα, Π͞Ρ͞Ο͞C = π(ατ)ρος, Χ͞Ω = χ(ριστ)ω; and even used in compound words or derivatives, e.g. Α͞Ν͞Ι͞Ν͞Ο͞Ϲ = αν(θρωπ)ινος, Π͞Ν͞Α͞Τ͞Ι͞Κ͞Ο͞Ϲ = πν(ευμ)ατικος, Ο͞Υ͞Ν͞Ι͞Ο͞Ϲ = ουρ(αν)ιος, Θ͞Τ͞Ο͞Κ͞Ο͞Ϲ = θ(εο)τοκος.
While these abbreviations are most common in Biblical and theological manuscripts, their use is not restricted to contexts where they have theological significance (e.g. Jesus may call himself Υ͞Ϲ ΤΟΥ Α͞Ν͞Ο͞Υ, i.e. υἱὸς τοῦ ἀνθρώπου, but we may also read a story about Α͞Ν͞Ο͞C TIC…, i.e. ἄνθρωπός τις).