Backward, forward, outward and similar words can be used as adjectives or adverbs. When these words are used as adjectives, they do not take –s.
- He was seen driving in a northward direction. (Here ‘northward’ is an adjective modifying the noun ‘direction’.)
- Africa is backward in many aspects.
When words like backward and forward are used as adverbs, they can be used with or without –s. Note that the forms backwards, forwards and northwards are more common in British English. Americans prefer the forms without –s.
- She was running backwards and forwards. (More common in British English)
- She was running backward and forward. (More common in American English)
- Let us go upwards. (British English)
- Let us go upward. (American English)
- We walked homewards. (British English)
- We walked homeward. (American English)
- We walked towards the railway station. (British English)
- We walked toward the railway station. (American English)
Note that we do not use –s in expressions such as look forward to, put forward and bring forward.
I look forward to meeting you soon. (NOT I look forwards to meeting you soon.)