A numeral is a symbol or group of symbols that represents a number. Numerals are not the same as numbers just as words are not the same with the things they refer to. The symbols “11(decimal)”, “1011(binary)” and “B(hexadecimal)” are different numerals, all representing the same number. The number is the idea, the numeral is anything that represents that idea.
MQTT (formerly known as MQ Telemetry Transport) was created in 1991 by Andy Stanford-Clark (IBM) and Arlen Nipper (Eurotech) in order to connect oil pipelines over unreliable, satellite networks. It is a machine-to-machine (M2M)/”Internet of Things” connectivity protocol.
It was designed as an extremely lightweight publish/subscribe messaging transport. It is mostly useful for establishing connections with remote locations where a small code footprint is required and/or network bandwidth is at a premium. The protocol is data-centric, unlike for example HTTP, which is document centric.