Correct spelling for the English word "lyday" is [lˈɪde͡ɪ], [lˈɪdeɪ], [l_ˈɪ_d_eɪ] (IPA phonetic alphabet).
Apologies, but "lyday" does not appear to have a recognized dictionary definition. It is possible that "lyday" could be a proper noun or a term that is not widely documented. Without further context or clarification, it is challenging to provide an accurate definition for this term. If you can provide additional information or context, I would be happy to assist you further.