Certainly, here's an explanation of each of these terms in simple language:

PkScript: This stands for "public key script," and is a type of script used in Bitcoin transactions to determine the conditions under which the funds can be spent. The PkScript is typically part of the output of a transaction, and it defines the requirements that the spender must meet to be able to claim the funds. The PkScript contains information about the type of script used, as well as any conditions or restrictions that must be met.

For example, a PkScript might specify that the funds can only be spent if the spender can provide a valid signature from a specific private key, or if they can provide a specific piece of data that matches a pre-determined hash.

Script Pubkey: This is another name for the PkScript, and is the output script of a Bitcoin transaction that determines the conditions under which the funds can be spent.

SigScript: This stands for "signature script," and is a type of script used in Bitcoin transactions to prove that the spender has the authority to spend the funds in question. The SigScript is typically part of the input of a transaction, and it contains a digital signature and other data that proves that the spender has the right to claim the funds.

For example, a SigScript might contain a signature from a specific private key, along with other data that proves that the signer is the rightful owner of the funds.