The phrase "specific index" refers to a particular, identified list or system used to measure or track something. It indicates that a precise and targeted measure or indicator is being referred to. Full definition
The headings that follow provide more detailed information on various indexes, including descriptions of specific indexes you might consider using. (us.etrade.com)
I think there is some real potential in using low cost country or region specific index funds to add diversity to your portfolio. (fatpitchfinancials.com)
Some may track sector - specific indices such as the global healthcare index or the Australian resources index. (moneysmart.gov.au)