The first interest payment (from dated date to first payment date) on a bond representing interest for a period of more than six months. A Short Coupon represents interest for less than six months.
Sometimes bonds are issued with a bond date of greater than six months from the issue date. Coupons after the initial, long coupon are every six months. A long coupon reduces the effective yield-to-maturity by reducing the income that can be earned from reinvestment of the coupon.
an interest payment on a bond that is issued more than 6 months prior to the first interest payment date