A meridian is always a line of longitude, so it would appear the web version is no different to the PPL Nav book version. A line of latitude is not a meridian, so the word 'all' only refers to longitude, not both lats and longs.
Meridian Defined:
A meridian (or line of longitude) is an imaginary arc on the Earth's surface from the North Pole to the South Pole that connects all locations running along it with a given longitude. The position of a point on the meridian is given by the latitude. Each meridian is perpendicular to all circles of latitude at the intersection points. Each is also the same size, being half of a great circle on the Earth's surface and therefore measuring 20,003.93 km.