Productivity culture loves its jargon. Here are the 20 terms you will run into everywhere, defined plainly and without mystique, each with the part actually worth remembering.

Goals & measurement

OKR (Objectives & Key Results)

A short-cycle goal system: one qualitative ambition, proven by 2 to 5 numeric results. Popularised by Intel, then Google. A healthy target is around 70 % attainment. → Full guide with 15 examples.

Key result

The numeric proof of an objective: a starting value, a target value, a deadline. It measures an outcome ("5 interviews booked"), never an activity ("50 applications sent").

SMART goal

A drafting grid: Specific, Measurable, Achievable, Realistic, Time-bound. Useful for writing a goal down, not sufficient on its own for deciding what matters. → OKRs vs SMART vs KPIs.

KPI (Key Performance Indicator)

A metric watched continuously to know the health of an activity. A thermometer, not a plan of action.

North star metric

The single metric meant to sum up the value a product delivers (nights booked, for Airbnb). A useful idea, as long as you do not change it every month.

Managing time

Time-blocking

Reserving calendar slots for your tasks instead of working as things come. The task becomes an appointment. → Full guide.

Time-boxing

Time-blocking with a hard stop: when the slot ends you stop, finished or not. The right tool against perfectionism and against tasks with no natural end.

Task batching

Grouping tasks of the same nature (email, invoices, calls) into one block to remove context switches.

Deep work

Cal Newport's term: fully concentrated work on a cognitively demanding task, without interruption. The scarcest and most productive resource in a working day.

Context switching

The cognitive cost of moving from one task to another. After an interruption it takes on average 23 minutes to get back to full concentration (Gloria Mark, UC Irvine).

The Pomodoro technique

Working in 25-minute intervals separated by short breaks. Effective for getting started when motivation is missing, less suited to real deep-work sessions, which it fragments.

Parkinson's law

"Work expands so as to fill the time available for its completion." The practical corollary: give a task less time and it compresses. That is the active ingredient in time-boxing.

Prioritising

The Eisenhower matrix

Sorting tasks along two axes (urgent, important) into 4 quadrants: do, schedule, delegate, delete. → Guide with examples.

MIT (Most Important Task)

The task, or the two or three tasks, that would make the day a success if they were the only thing you got done. Chosen in the morning, before email.

Eat the frog

Do the most unpleasant task first, while willpower is at its highest. Loosely attributed to Mark Twain, popularised by Brian Tracy.

Habits

Streak

The number of consecutive days a habit has been kept. A powerful motivator, provided you know that one isolated miss ruins nothing. → How long does it take to build a habit?

Habit stacking

Attaching a new habit to an existing routine: "after [current habit], I do [new habit]". A contextual trigger beats an abstract time of day.

Habit heatmap

A calendar grid where each day kept colours a cell, in the spirit of the GitHub contribution graph. It makes consistency, and the gaps in it, visible at a glance.

The two-day rule

Never miss a habit two days in a row. It rests on the research: an isolated miss has no measurable effect, it is the repeated miss that kills the habit.

The 21-day rule (a myth)

The idea that a habit forms in 21 days is a misreading of an observation by Maxwell Maltz. The science (Lally, 2009): a median of 66 days, ranging from 18 to 254.

From glossary to practice

All of these concepts live in one place in Cosmo: OKRs with progress computed for you, time-blocking by drag and drop, priorities to apply Eisenhower, and habits with heatmaps and streaks. Free, with an instant demo and no sign-up.