Colloquial, somewhat childish or old-fashioned word for cooked rice. Often used in nostalgic or affectionate contexts.
Grandma cooked rice for her grandchild.
The rice grandma cooked is the best.
Colloquial, somewhat old-fashioned or regional term for a meal or food in general. Often used in set phrases like おまんまの食い上げ (losing one's livelihood).
See also: まんま
I lost my job and now I can't even put food on the table.
I'm hungry, so let's eat.
飯 is a blunt, masculine colloquial word for rice or a meal, whereas おまんま carries a softer, nostalgic or childish tone.
食事 is the neutral, formal word for a meal, while おまんま (in its 'meal' sense) is casual and old-fashioned.
ご飯 is the standard, neutral word for cooked rice or a meal, while おまんま is a colloquial, nostalgic-sounding variant of the same word.
Kanji spelling using 御 for the honorific prefix; rarely used in practice.
Kanji spelling with お in kana and 飯 for 'rice'; very uncommon.
From the honorific prefix お and まんま, a nursery or colloquial word for cooked rice or food. まんま is also found without the prefix.