Haidar means "lion king", a powerful lion that is the leader among lions. Haidar is not a Quranic name, but Muslims can use it since it has a good meaning. It is pronounced [(H)ot + pr(AY)] + [(DU)st + p(R)ay] with emphasis on the first syllable. It is written as حَيْدَر in Arabic and can also be written as Haider, Heider, Haydar, Heydar in English.
For Ayaan please look at this page on our site: Ayan