The Mahajani script was a commercial script (महाजन mahajana is the Hindi word for ‘banker’) used across Northern India until the middle of the 20th century. It was used by speakers of a number of languages, including Hindi, Marwari and Punjabi, and was taught in special merchant- and business-focused schools alongside other skills required for conducting business.
Mahajani functions as an alphabet, but also displays some characteristics of an abugida. In theory, consonant letters contain an inherent [a] vowel, but there are no vowel diacritics to modify this vowel, so each consonant letter can also be used to represent a following [i], [i:], [u], [u:], [e], [o], [ai], or [au]. There are, however, independent vowel letters, which can be written after the consonant to indicate either that a vowel immediately follows the consonant or that a vowel follows the [a] inherent in that consonant. This means that the sequence ka + o can represent either [ko] or [kao]. Consonant clusters are equally ambiguous when written. There is no visible virama to cancel a post-consonantal vowel, so the elements of a consonant cluster are written sequentially using the full forms of regular consonant letters. So the sequence ka + ra can represent either [kra] or [kara]. This means that, in general, the value of a consonant must be inferred at the morphological level.
The term ‘mahajani’ is also sometimes applied to a merchant-specific style of writing another Indic script. For example, Mahajani Gujarati refers to the Gujarati script as it is used by Gujarati-speaking merchants. In this case, the characteristics of the Mahajani script proper may not be present.