For some time during pre-publication of the novel, the prospective trilogy was known in the UK as The Golden Compasses, an allusion to God's poetic delineation of the world. The term is from a line in Milton's Paradise Lost, where it denotes the drafting compass God used to establish and set a circular boundary of all creation:
Then staid the fervid wheels, and in his hand He took the golden compasses, prepared In God's eternal store, to circumscribe This universe, and all created things: One foot he centred, and the other turned Round through the vast profundity obscure— Book 7, lines 224–229
Meanwhile in the US, publisher Knopf had been calling the first book The Golden Compass (singular), which it mistakenly understood as a reference to Lyra's alethiometer (depicted on the front cover shown here), because of the device's resemblance to a navigational compass. By the time Pullman had replaced The Golden Compasses with His Dark Materials as the name of the trilogy, the US publisher had become so attached to its mistaken title that it insisted on publishing the first book as The Golden Compass rather than as Northern Lights, the title used in the UK and Australia.
God as architect, wielding the golden compasses, by William Blake (left) and Jesus as Geometer in a 13th-century medieval illuminated manuscript of unknown authorship.
In the film version, the alethiometer is specifically referred to as a golden compass.