I'm trying to understand QAM transmission and I'm struggling to understand this sentence, 'The advantage of using QAM is that it is a higher order form of modulation and as a result it is able to carry more bits of information per symbol. By selecting a higher order format of QAM, the data rate of a link can be increased. Article here'
Could someone explain what the term 'higher order form of modulation' means. Does it mean that the carrier frequency is higher?