Choja (or chosha) is a name for an elderly person or rich person.
Usage as Buddhist terminology
While Shakyamuni was alive, owners of large land or commercial capital owners, who belonged to wealthy class, were called koji (Buddhists). Among them, especially those who had social forces and in the position of representing the wealthy class were called choja. It has a meaning of supporters of Buddhism and examples are seen in many Buddhist scriptures including Hokekyo (Lotus Sutra).
Choja Gujiyu (a parable of a rich man and his poverty-stricken son) 'Hokekyo' Shingehon
Coming from a Buddhist terminology, it was also used in Chinese classics, meaning a high-profile person with fortune and virtuous deeds. Also in Japan, it was used to mean a representative who led the family such as in 'uji no choja' (the head of the clan) or to mean a wealthy person such as in "Warashibe Choja" (The Straw Millionaire).
Nowadays, the term 'choja' is rarely used by itself mundanely, but it remains in our daily life as set phrases such as 'Okuman choja' (Billionaire) and 'Choja Banzuke' (the list of biggest tax payers in Japan). In addition, expressions such as 'Kabu choja' (stock market billionaire) or 'Tochi choja' (property billionaire) may be used, in which 'choja' is capped with the means to get enormous fortune.