[ 'sʌɪləʊ ]
■ noun ( plural ~s )
1》 a tall tower or pit on a farm, used to store grain.
2》 a pit or other airtight structure in which green crops are compressed and stored as silage.
3》 an underground chamber in which a guided missile is kept ready for firing.
Origin
C19: from Sp., via L. from Gk siros 'corn pit'.