noun
Refers to the internal organs of animals, especially when used as food. Common in cooking contexts.
魚のわたを取り除いてから焼く。
Remove the fish guts before grilling.
この店のわた煮込みは絶品だ。
The stewed entrails at this restaurant are exquisite.
ホルモン refers to offal used in Japanese cuisine, especially grilled; わた is a broader term for guts and entrails, not limited to prepared dishes.
The origin is uncertain; possibly related to the idea of 'inside' or 'contents'. The kanji 腸 is an ateji applied later.