The character combination that opens the Guru Granth Sahib, rendered in roman letters as ik onkar, is written in Gurmukhi as a single fused symbol rather than as two ordinary words joined by normal orthographic rules, the numeral ik, one, prefixed directly onto onkar without the vowel markers a standard conjunction would require, producing a form that exists nowhere else in the script and that calligraphers and sign painters treat as a distinct emblem in its own right, reproduced on gateways, flags and pendants as a visual symbol independent of its function as opening text. That treatment as image rather than only as language has no real parallel among the other formulas in this atlas, most of which are transmitted purely as recited sound.
Translators disagree moderately about how much theological weight the numeral carries. Read simply, ik just means one, and onkar is the Punjabi and Sikh rendering of the Sanskrit Om, so the phrase states that Om, the divine syllable inherited from the wider Indian religious vocabulary, refers to a single, undivided reality rather than to a plurality of gods. Sikh theological writing goes further, treating the choice of the numeral one, rather than a word like ek that could carry the same meaning in ordinary prose, as a deliberate emphasis on divine uniqueness that resists dilution into the more common devotional vocabulary of the surrounding Hindu and Muslim traditions Guru Nanak was writing among, a claim about theological intention argued from the symbol's uniqueness in the script rather than demonstrated by any surviving statement from Nanak explaining his own choice.