megal - see Mega-.
Megal is a prefix that means “big”, “huge”. It is used to form words denoting very large units of measurement.
For example:
Megabyte is a unit of information equal to 1 million bytes.
Megawatt is a unit of power equal to 1 million watts.
Megahertz is a unit of frequency equal to 1 million hertz.
And so on. The prefix mega indicates that we are talking about a very large quantity of something. It is widely used in science and technology to denote large units of measurement.