The smallest unit of account on the Lightning Network. A millisatoshi is one hundred billionth of a single bitcoin. A millisatoshi is one thousandth of one Satoshi. Millisatoshis do not exist, nor can they be settled on the Bitcoin network. aantonop.com
Ps. 'millisatoshi' (msat) has to be used in the Lightning Network ⚡.
Keyword: Channel Fee, Hash-Time-Locked-Contracts (HTLCs), Base Fee, Time Lock Delta, Fee Rate