Fascinating discussion.
So here's my definition of a "tick chart".
RAW TICK CHART. This shows every Bid and Ask price change which your broker feeds to you. Faster brokers, more pricing data changes possible per unit time.
To me, Bars and Candles are really the same thing.
N TICK BAR. This is a Bar or Candle formed with OHLC (open, high, low, close price) data (using either the Bid or Ask price, but not both) which consists of a Fixed number (N) of Raw Quote Ticks from your broker. These "ticks" are not "transactions or trades" but merely successive updates of the Bid/Ask prices at the rate your broker provides.
N TICK BAR charts are an interesting correlated measure of how "excited" a market is, since more Bars/Candles are formed when quote data rates rise. Where excitement is defined as more quote changes per unit time, usually associated with more traders "jumping into" the market, perhaps also more "transactions" taking place but, remember...
Forex does not have Time and Sales as it is a decentralized market, and the brokers DO NOT want you to know the transaction flows which they COULD provide for you, since some brokers mediate actual trades and could inform us traders of the trades which execute. However, confidentiality and tradition in Forex mean that few if any offer a Time and Sales and it would be a "broker specific" or "exchange specific" Time and Sales. For example, LMAX could issue a Time and Sales since it is an "exchange".
HyperScalper