Which is correct?
The new high-bandwidth cabling system was designed to be ____________ with existing technology.
Answer: Either, depending on geography and your preferred style guide.
Backward is the preferred style in the United States and backwards in Britain. In Canada, where we use a mash-up of British/US vocabulary, use varies.
On the other hand, if you follow a particular style, you should consult your guide. If you want to be AP compliant, for example, make it backward.
“This is a point on which British and US usage differs. Here is advice from two usage guides.
R.W. Burchfield, The New Fowler’s Modern English Usage (OUP 1998):
backward(s) in most adverbial uses, backward and backwards are interchangeable, but usage varies subtly from person to person and from region to region. It is broadly true to say that in North America backward seems to be somewhat more usual than backwards, and in Britain the other way round … As an adjective, the only form used is backward (without a backward glance).
Bryan A. Garner, A Dictionary of Modern American Usage (OUP USA 1998):
Directional words A. The suffix -ward(s) In AmE, the preferred practice is to use the -ward form of directional words, as in toward, forward, westward. Words ending in -ward may be either adjectives or adverbs, whereas words ending in -wards, common in BrE, may be adverbs only … Two exceptions in AmE are the adverbs afterwards and backwards, which are almost universally used in preference to afterward and backward. It’s anomalous that most people say forward but backwards.
The Oxford English Dictionary records that backwards has been in use in English since the 16th century.”
See our definition of backward compatible.
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