unibody

Short definition from Wiktionary

Noun

1. 1
   An automobile construction technique in which the body is integrated into a single unit with the chassis rather than having a separate body-on-frame.
2. 2
   A body of this type.
3. 3
   A shell that is the principal source of structural strength of an object; also, its design and construction.
4. 4
   A style of mobile phone, tablet, or laptop computer where the user cannot replace the battery because the device is manufactured as a single sealed unit.