The fescalised portion on an undercarriage (or any actuator or jack) is the shiny machined bit. Its not in the English dictionary as it comes from the Greek word fescalise which basically means 'without cheese'. Greek shepherds used the phrase 'fescalised portion' to describe the 'shaft' of a goat's penis (a delicacy in Greece) which was held held between the thumb and forefinger while the 'helmet portion' was dipped in a jar of Feta
This what Giggle threw up. After 46 years on the spanners ( and laptops) you still live and learn.