original form; base form
Refers to the original shape or form of something before changes or modifications. Used in both concrete and abstract contexts.
この建物は原形をとどめていない。
This building no longer retains its original form.
動詞の原形を辞書で調べる。
Look up the base form of the verb in the dictionary.
The car was smashed so badly in the accident that it no longer resembled its original shape.
The restorer worked to return the mural to its original form.
Even after 100 years, this building retains its original form.