Earnings:
The amount of profit that a company produces during a specific period, which is usually defined as a quarter (three calendar months) or a year. Earnings typically refer to after-tax net income.Ultimately, a business's earnings are the main determinant of its share price, because earnings and the circumstances relating to them can indicate whether the business will be profitable and successful in the long run.

Earnings are perhaps the single most studied number in a company's financial statements because they show a company's profitability. A business's quarterly and annual earnings are typically compared to analyst estimates and guidance provided by the business itself. In most situations, when earnings do not meet either of those estimates, a business's stock price will tend to drop. On the other hand, when actual earnings beat estimates by a significant amount, the share price will likely surge. 

Federal Funds Rate:
The interest rate at which a depository institution lends funds maintained at the Federal Reserve to another depository institution overnight. The federal funds rate is generally only applicable to the most creditworthy institutions when they borrow and lend overnight funds to each other. The federal funds rate is one of the most influential interest rates in the U.S. economy, since it affects monetary and financial conditions, which in turn have a bearing on key aspects of the broad economy including employment, growth and inflation. The Federal Open Market Committee (FOMC), which is the Federal Reserve’s primary monetary policymaking body, telegraphs its desired target for the federal funds rate through open market operations. Also known as the “fed funds rate".

The higher the federal funds rate, the more expensive it is to borrow money. Since it is only applicable to very creditworthy institutions for extremely short-term (overnight) loans, the federal funds rate can be viewed as the base rate that determines the level of all other interest rates in the U.S. economy.
 
Banks and other depository institutions maintain accounts at the Federal Reserve to make payments for themselves or on behalf of their customers. The end-of-the-day balances in these accounts are used to meet the reserve requirements mandated by the Federal Reserve. If a depository institution expects to have a larger end-of-day balance than it needs, it will lend the excess amount to an institution that expects to have a shortfall in its own balance. The federal funds rate thus represents the interest rate charged by the lending institution.
 
The target for the federal funds rate – which as noted earlier is set by the FOMC – has varied widely over the years in response to prevailing economic conditions. While it was as high as 20% in the inflationary early 1980s, the rate has declined steadily since then. The FOMC has maintained the target range for the federal funds rate at a record low of 0% to 0.25%, from December 2008 onward, to combat the Great Recession of 2008-09 and stimulate the U.S. economy.

Economic Activity: 
The production and distribution of goods and services at all levels. Economic activity and expected future levels of it have an important influence on security prices because of the interrelationship between economic activity and corporate profits, inflation, interest rates, and other variables. One frequently used measure of economic activity is the gross domestic product.

Yield Curve:
A line that plots the interest rates, at a set point in time, of bonds having equal credit quality, but differing maturity dates. The most frequently reported yield curve compares the three-month, two-year, five-year and 30-year U.S. Treasury debt. This yield curve is used as a benchmark for other debt in the market, such as mortgage rates or bank lending rates. The curve is also used to predict changes in economic output and growth.

The shape of the yield curve is closely scrutinized because it helps to give an idea of future interest rate change and economic activity. There are three main types of yield curve shapes: normal, inverted and flat (or humped). A normal yield curve (pictured here) is one in which longer maturity bonds have a higher yield compared to shorter-term bonds due to the risks associated with time. An inverted yield curve is one in which the shorter-term yields are higher than the longer-term yields, which can be a sign of upcoming recession. A flat (or humped) yield curve is one in which the shorter- and longer-term yields are very close to each other, which is also a predictor of an economic transition. The slope of the yield curve is also seen as important: the greater the slope, the greater the gap between short- and long-term rates. 

Core Inflation:
A measure of inflation that excludes certain items that face volatile price movements. Core inflation eliminates products that can have temporary price shocks because these shocks can diverge from the overall trend of inflation and give a false measure of inflation.

Core inflation is most often calculated by taking the Consumer Price Index (CPI) and excluding certain items from the index, usually energy and food products. Other methods of calculation include the outliers method, which removes the products that have had the largest price changes. Core inflation is thought to be an indicator of underlying long-term inflation.