(countable, uncountable) UK, Canada, and Australia spelling of ardor.
The purpose of my visit, and the frightful abnormalities it postulated struck at me all at once with a chill sensation that nearly over-balanced my ardour for strange delvings. 1931, H. P. Lovecraft, chapter 6, in The Whisperer in Darkness:
I rushed towards her, and embraced her with ardour; but the deathly languor and coldness of the limbs told me, that what I now held in my arms had ceased to be the Elizabeth whom I had loved and cherished. 1816 June – 1817 April/May (date written), [Mary Shelley], chapter VI, in Frankenstein; or, The Modern Prometheus. […], volume III, London: […] [Macdonald and Son] for Lackington, Hughes, Harding, Mavor, & Jones, published 1 January 1818, →OCLC, page 120: