The rules that use the vocabulary item "eight" are:

<hour>

eight

oh eight

zero eight

one eight

<digit-not_zero>

eight

<digit-pl>

eight

<scale_number-gapsout_null-gapsin_null>

eight hundred

eight hundred fifty

eight thousand

eight thousand five hundred

eight hundred thousand

eight hundred fifty thousand

<air_call_sign_designator>

dash eight

<digit_not_one>

eight

<digit>

eight

<digit-not_zero-pl>

eight

<digit-8>

eight

<digit_one_to_eight>

eight