An ETF basket refers to the underlying securities held by an exchange-traded fund (ETF). An ETF basket typically consists of a collection of stocks, bonds, or other securities that are chosen to reflect the performance of a specific index, sector, or investment theme.
This is the link between how a stock is doing relative to the market and it can also be used to see how an ETF is doing in their set market. This is a good statistic to use when you want to see how responsive a stock or ETF is to market activity, higher being more responsive.
This is the spread that people are willing to pay (bid) and sell (ask) their ETF or stock for. This means that as the spread gets wider it becomes increasingly more expensive to purchase and own.