One in six stops making appearances (11)

'appearances' is the definition.
(a visitation is an appearance or apparition)

'one in six stops' is the wordplay.
'one' becomes 'I' (Roman numeral).
'in' indicates putting letters inside.
'six' becomes 'VI' (Roman numerals).
'stops' becomes 'stations' (as in train stops).
'vi'+'stations'='vistations'
'i' inserted inside 'vistations' is 'VISITATIONS'.

'making' is the link.