implicit conversion
Computing term for automatic type conversion performed by a compiler or interpreter without explicit instruction.
C言語では、型の暗黙変換が行われることがある。
In C, implicit type conversions may occur.
Explicit conversion, where the programmer specifies the conversion, as opposed to implicit conversion.
Compound of 暗黙 (implicit) and 変換 (conversion), likely a calque from English 'implicit conversion'.