Second son, crossing pitch, means to walk tall (6)
I believe the answer is:
stilts
'to walk tall' is the definition.
I can't judge whether this defines the answer.
'second son crossing pitch' is the wordplay.
'second' becomes 's' (common abbreviation).
'son' becomes 's' (genealogical abbreviation for son).
'crossing' indicates putting letters inside (to cross can mean to go over or around).
'pitch' becomes 'tilt' (synonyms).
's'+'s'='ss'
'ss' placed around 'tilt' is 'STILTS'.
'means' is the link.
Can you help me to learn more?
(Other definitions for stilts that I've seen before include "Tall sticks for lofty walking" , "Poles used for walking high above the ground" , "Long sticks for elevated walking" , "Sticks to help you walk tall" , "Walking poles; birds" .)