Summary of the symbols in the Ethereum Yellow Paper.

Can be used as a reference and support for building and Ethereum client.

General

Symbol	Symbol name (in Math or plain english)	Meaning in the yellow paper
	mu	Machine state
	sigma	World State
	Greek small letter delta	Number of items on the stack required for a given operation
		Ethereum State transition function
		Transaction state accumulation function
	C	General cost function
		Cost function for the SStore operation
	KEC	Keccak256 fash function (also referred as plain Keccak)
	KEC512	Keccak512 hash function
	RLP
	TRIE	Build the Merkle-Patricia tree?
	POW	Proof of Work function

Account state

Symbol	Symbol name (in Math or plain english)	Meaning in the yellow paper
		Account state (of account a)
		Nonce for account a in state
		Storage root hash of account a
		CodeHash of account a
		Balance of account a
	Dead account	Describe when an account at address a is dead in the world state (= see also EMPTY)
	Empty account	Describes when the account state at address a is non-existent or empty.

Symbol	Symbol name (in Math or plain english)	Meaning in the yellow paper
	T	Ethereum transaction
		Nonce (= number of transactions sent by the sender)
		gasPrice
		gasLimit
		Message call recipient (`to`)
		value: number of Ether (in Wei) to be transferred to the recipient. NB: for contract creation, the field acts as an endowment
		`r`and `s`fields of a transaction signature (see Appendix F of the yellow paper)
		`data`: Unlimited size by array specifying the input data of the message call

Symbol	Symbol name (in Math or plain english)	Meaning in the yellow paper
		Receipt of the ith transaction
		Receipt
		Set of logs created through execution of the transaction
		Bloom filters composed from information in those logs
		Status code of the transaction
		Log entry
		Logger address
		Log topic (32-byte in size, possible empty series)
		Some number of byte of data
	M	Bloom filter function, applied to a log entry `O`. Reduce a log entry into a single 256-byte hash.

Symbol	Symbol name (in Math or plain english)	Meaning in the yellow paper
		Current Block header
		New block header
		`T` = Transaction List of transactions included in the block
		`U` = Ommer block header (also called uncle block, but [ommer is a gender neutral] term(https://nonbinary.miraheze.org/wiki/Gender_neutral_language_in_English#Aunt/Uncle) for "sibling of parents") List of ommer block headers
		`U` = Ommer block header (also called uncle block, but [ommer is a gender neutral] term(https://nonbinary.miraheze.org/wiki/Gender_neutral_language_in_English#Aunt/Uncle) for "sibling of parents")
		Parent hash ( = previous hash)
		Ommers Hash.
		Fee Beneficiary (collected from successful mining)
		stateRoot
		transactionRoot
		receiptsRoot
		logsBloom
		Difficulty
		Number
		Gas Limit
		Gas used
		Timestamp
		ExtraData
		MixHash
		Nonce
		List of transactions
		Block ( = current block header, list of transactions, ommer blocks' header)

Symbol	Symbol name (in Math or plain english)	Meaning in the yellow paper
		Parent block of B
		Block number ( = parent block number incremented by one)
		Canonical Difficulty of a block header
		Current DAG ( = large data set needed to compute the mix-hash)
		Block Header Validity function
		Byte sequence given as the output data of a message call
		Set of scalar non-negative integers
		Set of all byte sequences
		First item on the machine stack.
	Box	First 32 items of the machine’s memory.
		Unmodified input value
		Modified (utilisable) input value
		Intermediate values
		Function
		Similar, element-wiser version of the function mapping instead between sequences.
		Common function that evaluates to the last item in a sequence.
		Account validity function