Old English ilca 'same', of Germanic origin; related to alike
Today ilk is used in phrases such as of his ilk and of that ilk to mean ‘type’ or ‘sort’. This sense arose out of a misunderstanding of the earlier, Scottish use in the phrase of that ilk, where it means ‘of the same name or place’. For this reason, some traditionalists regard the modern use as incorrect. It is, however, the only common current sense and is now part of standard English.