# 5. Terminology

Rune mints can be open (allowing anyone to mint) or closed, subject to terms:

**Cap**: Total mintable supply Amount: Units created per mint.

**Start/End Height:** Blocks between which minting is allowed Start/End Offset: Blocks from etching between which minting is allowed

**Minting:** When a mint is open per its terms, anyone can mint that rune by creating new units up to the cap.

**Transferring:** Input runes transfer to outputs, modulated by Runestone edicts (rune ID, amount, output) and pointers specifying a default output. Remaining unallocated runes follow the runestone pointer or first non-OP\_RETURN output.

**Burning:** Runes can "burn" (destroy) by transferring to OP\_RETURN outputs via edicts/pointers.

**Cenotaphs:** Invalid Runestones with malformed data are "cenotaphs". Input runes are burned, etched runes are unmintable, and minted runes burn - though counting against the cap.

Cenotaphs allow introducing new runestone semantics in the future, while appearing to legacy clients as simply burning runes instead of relocating them unpredictably.