hi bob thanks for confirming this. But what is meant by private keys?
Read:
https://en.bitcoin.it/wiki/Private_key 
so basically at the time of the fork, my bch was in electron cash right?
No... For the millionth time... Coins ARE NOT kept in wallets... Private keys are kept in wallets.
The "ownership" of coins by public keys (which are derived from private keys) is recorded on the blockchain.
You can prove you control the public key by signing a transaction using the associated private key... Without the private key, you can't sign a transaction... And you can't "spend" coins.
While other ppl might have it in their nano ledger s, coinbase or binance etc?
Coinbase or binance (and other exchanges/service providers) generally control a bunch of private keys... In the case of the BCH fork they had control of the BTC private keys which matched public keys on the BCH blockchain... users again, were given nothing more than an "account balance" that says "we owe this user X coins"...
It was only because of public outcry that the bigger exchanges even credited users with the BCH (again, this was just an "account balance"... They did not give users private keys etc)... Some exchanges (and other service providers) did not do this... and made huge amounts of money by keeping all the BCH for themselves.
Ledger Nano S users on the other hand "control" the private keys via controlling the device (and/or being able to restore using the seed mnemonic)... Ledger then implemented a change in the wallet software that allowed users to transact on the BCH network using their device.
Prior to that update... A Ledger Nano S user would need to have used their seed mnemonic to derive their private keys (either by importing their seed mnemonic into a BCH compatible wallet that supported seed mnemonics, like Electron Cash... And having that wallet derive the private keys... or by using some other tool to derive the private keys manually and then importing the private keys into a BCH compatible wallet).
