Correct spelling for the English word "Defenced" is [dɪfˈɛnst], [dɪfˈɛnst], [d_ɪ_f_ˈɛ_n_s_t] (IPA phonetic alphabet).
The word "defenced" is not a common English word. It is likely a variant or archaic form of the word "defensed", which means to protect or guard something. The etymology of "defensed" traces back to the Old French word "defendre", which means "to defend". This Old French word is derived from the Latin word "defendere", formed from the combination of the prefix "de-" (meaning "from" or "away") and the root "fendere" (meaning "to strike" or "to ward off"). Hence, the word "defenced" (if it is indeed a variation of "defensed") shares its origins with the concept of protection and safeguarding.